I'm currently creating my first custom theme for Tumblr and I can't find any explanation of how permalink pages for posts and that post's notes work or how they are written, how do I go about this? what is the code needed and where is it implemented?
Anything you want to appear on a permalink only page you want to have wrapped in block:PermalinkPage tags. If you only want it to show on the index page, wrap it in block:IndexPage tags.
To get your notes to show use {block:PostNotes}{PostNotes}{/block:PostNotes}. This will only appear on a permalink page (despite it not being wrapped in block:PermalinkPage tags. {PostNotes} creates an ol tag with a class of notes for you to style in any way you'd like.