At 1:13pm Jan 6, 2021 Trump ended his speech saying: "I know that everyone here will soon be marching over to the Capitol building to peacefully and patriotically make your voices heard." The Jan6 sham committee always plays that with the "..to peacefully and patriotically make your voices heard" clipped off.Not only was it more than 3 hours
Just after 2pm windows were broken and the Capitol was sieged.
At 3:13pm Trump tweets: "I am asking for everyone at the U.S Capitol to remain peaceful. No violence. Remember, we are the party of law and order. Respect the law and our great men and women in blue. Thank you."
That is a 1 hour and 13 minute delay from the start of the break-in. I have no idea exactly when Trump first learned of the Capitol siege.