I seriously doubt there’s a single piece of paper tying Trump to the January 6 insurrection. Other than the documents produced by the White House that the January 6 committee already has.
Trump is famous for not writing anything down, sending emails or leaving a paper trail anywhere. That’s why he was tearing up documents and stuffing the pieces down the toilet when he was in the White House. That’s why he gets angry about lawyers taking notes of their conversations.
The legal term is “plausible deniability”. Trump can deny he ever said, or ordered anybody to do anything because there’s no evidence that he did, unless it’s on a audio recording. Then, when his crimes and schemes are exposed, he throws some underling under the bus, and lets them go to jail while denying he had anything to do with their crimes. See Michael Cohen, Rick Gates,Papageorgio, and others.
Why do you think everybody’s tape recording him when they meet with him or talk on the phone?
Roger Stone hired several of the now convicted of seditious conspirators, as his personal bodyguards in the weeks before January 6th.
Stone, Bannon, Guiliani and all the players in the War Room in the Washington Hotel, many of whom would have been able to speak directly with Trump, could easily coordinate with the Proud Boys in their planning.