Hello i am trying to remove and install the transmission for a 2001 buick park avenue my self. any idea where i can start like a diagram on how to ?

This writeup is for a bonneville, but they both have the same transmission and engine. It should give you a decent idea of whats involved...
https://www.gmforum.com/mechanical-134/remove-transmission-primarily-96-99-a-289278/

But it also depends on how you plan on taking it out. Are you going out through the top or bottom of the engine bay? If you prefer to take it out through the top, you can pull both the engine and trans out at once, or seperatley without having to remove half the sub-frame assembly. Of course, I'm not sure if you have the one piece aluminum frame or the 2 piece steel frame.

Another question is, why are you pulling the trans?