Here is what I think Trump, Giuliani, Meadows, Navarro, Bannen and all the other people involved in this coup attempt were trying to do. I don't think the sequence is 100% exact, and there will be a lot more detail, but IMO, its not far off.
• Submit the forged documents from the slate of fake electors in Arizona, Georgia, Michigan, New Mexico, Nevada, Pennsylvania and Wisconsin to the National Archives (this will come into play later)
• Send the Jan 6 insurrectionists to the Capitol.
• Among that large group were certain participants who had a specific target in mind... not Pence or Pelosi, but the Senate Parliamentarian's Office, where the Electoral College ballot documents are kept. They ransacked that office looking for them, not realizing that the cases of ballots had already been taken to the Chamber.
• "Disappear" all those ballot documents.
• Copies of the missing ballots would then be retrieved from the National Archives, including the fake ones purporting to be the real ones from Arizona, Georgia, Michigan, New Mexico, Nevada, Pennsylvania and Wisconsin.
• This would switch 84 EC votes from Biden to Trump making Trump the president by 316-222
Three things happened that undid their plan.
1. Some of the forged EC documents were spotted ahead of the count (some as early as December 6)
2. Pence either knew of, or was told, what was going on and wouldn't play ball. This is why all those extra words and phrases were spoken by him as he opened each envelope to make it clear that the EC Votes he was counting were genuine (a message to the plotters that their plan had failed?)
3. The cases of Ballots had already left the Parliamentarians office before the ransackers got there.
Worth noting: I'm told the second-floor office of the Senate Parliamentarian's is not very easy to find, yet those ransackers knew exactly where it was and went straight there. Now, all those unauthorized Capitol tours hosted by people like Taylor-Greene and Boebert in the days before the insurrection make perfect sense don't they.