Just select efnet as a server and put in w/e name and #SFxT in channel
An alternative web client for efnet is
Webchat login is on the right, the usual, put in any nickname and then #SFxT.
Alternatively, you can use mIRC or other IRC clients.
You click on tools, then options, click on Efnet folder, pick a relevent server, put in nickname and tick the “new window box” and connect! The channel is #SFxT, so type in /join #SFxT