I'd start with a book before blindly jumping in to removing and tearing your engine down. See if it is something you
really want to do. Regardless, it's the best $25 you'll spend and should you decide to go it on your own you'll need it anyway.
https://www.pelicanparts.com/catalog/SuperCat/911M/POR_911M_TOLBKS_pg1.htm#item2
Porsche How to Rebuild and Modify Porsche 911 Engines, by Wayne R. Dempsey