Instructions have been followed. Interface is connected correctly and I have audio. When in a room, I show up to others as “channel 0” and I cannot be heard. What is wrong?

Hi MLB67,
Is the Send button enabled in the loewr-right corner of the jammr window?

If you are on Mac then it could be that the Microphone permission that allows applications to record audio has not been enabled for jammr. This page from Apple shows how to enable it:
https://support.apple.com/guide/mac-help/control-access-to-your-microphone-on-mac-mchla1b1e1fe/mac