The PAPI Component Repository is implemented in MediaWiki, just like Wikipedia. That means that if you know how to edit Wikipedia pages, or any other MediaWiki site, you know how to edit Component pages. If not, here's a link to the authoritative MediaWiki Editing Help
Once you have an approved account, you can edit any page in the repository. Keep in mind that a history is kept of all edits, so we know who you are!
When you first create a component page, you will be guided through the creation process by filling out a form with required information. After you have completed the form and your new component page is created, you can edit the contents either with the regular editing commands, or by reusing the form.
If you get too far afield, you can always delete the page and start over again. Use other component pages as examples of what you might want yours to look like.
Don't hesitate to borrow stuff from other pages. Copying code is a time-honored hallmark of an efficient (albeit lazy) programmer.
Here's an example of a skeleton Component Page.