I see repeated problems with new users not realising that it is necessary to connect to a server to hear ones self and set the input volume. I see this both on the forum and among the groups I am helping to get up-and-running with Jamulus.
A startup wizard would be a neat solution, but an even simpler solution could be a message in the center of the mixer window when it is empty, i.e. not connected to a server, to the effect of "Please connect to a server to hear yourself and others".
A second Connect button could be placed under the message.
Further the Input level "LEDs" could be grayed out when not connected to pass on the message you need to do something before you can hear yourself.

Strangely enough the biggest problem I have seen with the new groups around me is setting the input volume correctly. Not too quiet so you can't be heard, but not too loud to cause clipping distortion, which is always blamed on poor audio quality in Jamulus. Once the input volume is set right everyone is smiling.
Don