Trump was not happy with how the election turned. He lost by around 7 million votes, and also lost the Electoral College vote by quite a bit. But typical Trump, even before the votes were cast, was saying that if he lost, the vote had to be rigged. So then he went on his "whining (not winning) tour," where he continued to stoke up his base. So after the election the House would have to validate the vote — to confirm the vote was accurate, fair, and Biden won.
Jan. 6 was the date that the House was scheduled to confirm the election results. So was it just a coincidence that Trump decided that he would have a rally of his most ardent MAGA fans just a few miles from the Capitol on the date they would confirm the election results? And was it just a coincidence that many of the Trump supporters came to Washington, DC, with body armor, bear spray, etc.?
So in his rally, Trump said to the crowd, that the election was stolen, and if they didn't do something about it, they would lose their country. Then the crowd heard from the former New York mayor, Rudy Giuliani, who basically repeated Trump's claims, and went on about "Trial By Combat."
Finally, Trump said to this riled up crowd, “We are going to march to the Capitol,” and he said he would go along with them. So the mob headed for the Capitol, and the riotous scene is recorded for posterity.
When the dust settled, Senate Majority Leader Mitch McConnell and the GOP House Leader Kevin McCarthy both came out and blamed Trump for setting the stage for those treasonous acts. They lambasted him, but that did not last long. The House realized that, like the 9-11 Hearings, this attempted coup of our government needed to also have a hearing to determine how such a thing could happen. But alas, the cowards McConnell and McCarthy decided a hearing was not needed and both "whipping" their members to vote for no hearing.