I want to ask something about shipping a game and the Royalty Report

I am starting with Unreal Engine and i know that i need to pay a 5% royalty on that amount after the first $3,000 per game per calendar quarter. I know that if i need to pay royalty i need to fill a SUBMIT ROYALTY REPORT form to send to Epic to let them know about my revenue. But if do not need to pay the royalty (because my game are free or my revenue in that calendar quarter does not reach $3000), do i need to fill that form to send to Epic ? How can they know if someone does not send the REPORT form ? Do free games need to send this revenue-tracking to Epic per calendar quarter too?
And another question that when i ship my game, i need to fill another form call SUBMIT RELEASE FORM. Do i need to submit that form before i compile my game in shipping mode? If i want to release my game on Steam, how this form work?