The single best way to learn about creating content is to "just do it". Experiment and check things out. But while experimenting, please remember this: since you created the content you can also delete it. If you create some "test" content remember to delete those tests so I don't have to.
Right now, not only you are learning this new site but so am I. There's a huge difference between doing a prototype site with test users and doing debianHELP live with thousands of real users.
With that in mind, your options to create content may change as I define new roles for users and try to put as much responsibility and management for content as possible into the hands of users.
add more...
- add a verbose page w/screenshots for each content type.