When running the iTalc master while logged in as a user on a thin client, iTalc will overwrite your settings and automatically add any LTSP clients it finds to a classroom called 'LTSP'. You may temporarily add thin-clients to your setup by selecting 'Classroom Manager' from the left-most tabs, then right-clicking and selecting 'Add Computer'. The IP/Hostname field should be entered as $SERVERIP:10???, where $SERVERIP is your server's IP (When dealing with servers with multiple NICs you should enter the IP of the NIC serving the subnet of the client you wish to add), and ??? is the last-three digits of the thin client's IP.