diff --git a/Server/src/main/java/uulm/teamname/marvelous/server/netconnector/UserManager.java b/Server/src/main/java/uulm/teamname/marvelous/server/netconnector/UserManager.java
index d4fec75..627bd1a 100644
--- a/Server/src/main/java/uulm/teamname/marvelous/server/netconnector/UserManager.java
+++ b/Server/src/main/java/uulm/teamname/marvelous/server/netconnector/UserManager.java
@@ -8,15 +8,18 @@ import uulm.teamname.marvelous.gamelibrary.messages.ErrorMessage;
 import uulm.teamname.marvelous.gamelibrary.messages.client.*;
 import uulm.teamname.marvelous.gamelibrary.messages.server.HelloClientMessage;
 import uulm.teamname.marvelous.server.Server;
+import uulm.teamname.marvelous.server.lobbymanager.LobbyManager;
 import uulm.teamname.marvelous.server.lobbymanager.Participant;
 
 import org.java_websocket.WebSocket;
 
 import java.util.*;
 
-/** Class that manages users. It is meant as an extension to the {@link MarvelousServer} class, and should not be called
- * from anywhere else. This is the first place where messages are relayed to after they get received. This class is
- * responsible for handshakes, reconnects and WebSocket-to-Participant matching. <b>It is not thread-safe.</b>
+/** Class that manages users. It is meant as an extension to the {@link MarvelousServer} class. This is the first
+ *  place where messages are relayed to after they get received. This class is
+ * responsible for handshakes, reconnects and WebSocket-to-Participant matching.
+ * It is designed to be thread-safe. The Singleton of this class also contains a
+ * {@link LobbyManager}, which manages the lobbys.
  */
 public class UserManager {
 
@@ -33,6 +36,10 @@ public class UserManager {
         return instance;
     }
 
+    /** The {@link LobbyManager} associated with the {@link UserManager}. It is therefore a kind of extension
+     * to the current singleton, and may of course not be called from anywhere else */
+    private final LobbyManager lobbyManager;
+
     /** A set of users that aren't assigned to lobbies or character selection yet */
     private final HashSet<WebSocket> newUsers;
 
@@ -64,12 +71,19 @@ public class UserManager {
         this.readyToReconnect = new HashMap<>();
         this.inGame = new HashMap<>();
         this.activeParticipants = new HashMap<>();
+
+        Logger.trace("Instantiating LobbyManager with message sending callbacks");
+        this.lobbyManager = new LobbyManager(this::sendMessage, this::sendError);
+
+        Logger.trace("Instantiating JSON with the server's CharacterConfig");
         this.json = new JSON(Server.getCharacterConfig());
     }
 
     /** Called on a new WebSocket connection. Places the WebSocket and its ResourceDescriptor in a HashMap. */
     void connectUser(WebSocket conn) {
-        newUsers.add(conn);
+        synchronized (newUsers) {
+            newUsers.add(conn);
+        }
     }
 
     /**
@@ -106,7 +120,15 @@ public class UserManager {
                 } else if (parsedMessage instanceof PlayerReadyMessage) {
                     Logger.trace("Message is instanceof PlayerReadyMessage, assigning lobby");
                     assignLobby(conn, (PlayerReadyMessage) parsedMessage);
-                } else {
+                } else if (parsedMessage instanceof CharacterSelectionMessage) {
+                    Logger.trace("Message is instanceof CharacterSelectionMessage, passing to LobbyConnection");
+                    charactersSelected(conn, (CharacterSelectionMessage) parsedMessage);
+                } else if (parsedMessage instanceof RequestMessage) {
+                    Logger.trace("Message is instanceof RequestMessage, passing to LobbyConnection");
+                    relayRequestMessage(conn, (RequestMessage) parsedMessage);
+                }
+
+                else {
                     Logger.debug("Message '{}' has invalid type, Error will be sent");
                     sendError(conn, String.format(
                             "Message '%s' has invalid type, and cannot be processed on the server",
@@ -186,13 +208,48 @@ public class UserManager {
     }
 
     void assignLobby(WebSocket conn, PlayerReadyMessage message) {
-        // TODO: Assign a lobby
+        if (readyToReconnect.containsKey(conn) || readyToConnect.containsKey(conn)) {
+            if (readyToConnect.containsKey(conn)) {
+                synchronized (readyToConnect) {
+                    readyToConnect.remove(conn);
+                }
+            } else {
+                synchronized (readyToReconnect) {
+                    readyToReconnect.remove(conn);
+                }
+            }
+            synchronized (inGame) {
+                var participant = lobbyManager.assignLobbyToConnection(conn, "SomeName", message);
+                inGame.put(conn, participant);
+            }
+        } else {
+            Logger.debug(
+                    "WebSocket {} sent PlayerReadyMessage to server while not ready to connect, sending error",
+                    conn);
+            sendError(conn, "Invalid message, as client is not ready to connect");
+        }
     }
 
     void charactersSelected(WebSocket conn, CharacterSelectionMessage message) {
+        if (inGame.containsKey(conn)) {
+            lobbyManager.relayMessageToLobby(inGame.get(conn), message);
+        } else {
+            Logger.debug(
+                    "WebSocket {} sent CharacterSelectionMessage to server while not ingame, sending error",
+                    conn);
+            sendError(conn, "Invalid message, as client is not ingame");
+        }
     }
 
-    void relayRequestMessage(Participant conn, RequestMessage message) {
+    void relayRequestMessage(WebSocket conn, RequestMessage message) {
+        if (inGame.containsKey(conn)) {
+            lobbyManager.relayMessageToLobby(inGame.get(conn), message);
+        } else {
+            Logger.debug(
+                    "WebSocket {} sent RequestMessage to server while not ingame, sending error",
+                    conn);
+            sendError(conn, "Invalid message, as client is not ingame");
+        }
     }
 
     void disconnectUser(WebSocket conn, boolean closedByRemote) {
@@ -200,22 +257,33 @@ public class UserManager {
         synchronized (newUsers) {
             newUsers.remove(conn);
         }
+        synchronized (readyToConnect) {
+            readyToConnect.remove(conn);
+        }
+        synchronized (readyToReconnect) {
+            readyToReconnect.remove(conn);
+        }
         synchronized (inGame) {
             inGame.remove(conn);
         }
     }
 
-    public void sendMessage(WebSocket conn, BasicMessage message) {
-        var jsonRepresentingMessage = json.stringify(message);
-        if (jsonRepresentingMessage.isEmpty()) {
-            Logger.warn("Message {} could not be serialized!", message);
+    void sendMessage(WebSocket conn, BasicMessage message) {
+        Logger.trace("Sending message to WebSocket {}", conn);
+        if (conn == null) {
+            Logger.debug("Message sent to non-existent websocket, ignoring");
         } else {
-            conn.send(jsonRepresentingMessage.get());
+            var jsonRepresentingMessage = json.stringify(message);
+            if (jsonRepresentingMessage.isEmpty()) {
+                Logger.warn("Message {} could not be serialized!", message);
+            } else {
+                conn.send(jsonRepresentingMessage.get());
+            }
         }
     }
 
     /** Sends an {@link uulm.teamname.marvelous.gamelibrary.messages.ErrorMessage} to the specified user. */
-    public void sendError(WebSocket conn, String error) {
+    void sendError(WebSocket conn, String error) {
         Logger.debug("Sending error message '{}' to WebSocket {}", error, conn);
         var errorMessage = new ErrorMessage();
         errorMessage.message = error;
@@ -230,6 +298,7 @@ public class UserManager {
     }
 
     public int getUserCount() {
+        // FIXME: This is bugged at the moment
         return newUsers.size() + readyToConnect.size() + readyToReconnect.size() + inGame.size();
     }