http://git.chat98.i2p/chat98/chat98/commit/226b8ada293b78b9ac4aba723c9f099cafa80194?style=split&whitespace=ignore-all&show-outdated=
Once a username has been set, you will be brought to your buddies list. This should be blank on fresh installs. To add a buddy, click the + icon at the top, and paste their public key that they have shared with you. If they're online, you should see them appear as such, with the username they've set.