"Step 3: Go down to the panel that shows which online friends are playing Trove. Go to one of them and select ‘Join Session’. If it just says ‘Start’, go up to your online friends page and wait for a few moments. Then, try looking for the ‘Join Session’ button"
Is this in steam you mean as I play trove without steam.

Otherwise I have no idea what panel of friends I can see outside the game.