How do i use PDF Templates

PDF’s in custom modules is not an included feature, though some people have managed to get it working.

Are you sure you need a custom module? Doing things with basic modules greatly facilitates things in SuiteCRM, due to all the extra features that are already there.

Maybe you can get a few strategic ideas from my introduction in this post here:
SuiteCRM Concepts Explained: Accounts, Contacts and Sub-Accounts – SuiteCRM In-depth – pgorod's collection of articles on SuiteCRM