All that the protesters had to do was hinder the certification of the election on that day, Jan 6. In that event occured, then the House of Representatives would choose the President as they did in 1824. Each state gets 1 vote. Republicans states outnumbered the Dem states, so Trump would have been elected by the House.
You constantly need things spelled out for you, but I'm not your civics teacher. God knows you need one. You also lack critical thinking skills, but that can be overcome. It will take effort on your part, though. ;-)