metal roofing question

What is the practice for applying the self sticky underlayment (TRI Built) on my shed roof before installing the metal panels. Do you stick the paper up over the peak of the roof and is this sufficient to prevent water from coming in. Or do I need a foam sealant before the paper? I also understand that the ridge cap is fastened only to the roof panel and not the substrate correct? Thank you.

 

I have no idea, but if it was me I’d lay one side up and over, then again with the other side for two layers at the ridge… I mean assuming you’re not installing a ridge vent.