The list of active connections lists all users currently connected to your PC or just attempting to connect (in which case they will be listed as Authorizing). You can view the duration of connection, bytes sent and received, and the peer IP address for each connection. The "Disconnect All" button lets you disconnect all currently connected clients. The "Disconnect Selected" button lets you disconnect only selected clients. To select a single connection, click on it. To select multiple connections, hold Ctrl key while clicking on individual connections.