Hi and welcome, Kriss!
You're welcome! We're glad you got the first part sorted!
What in particular are you confused about assigned categories, restricted content, and group users? Are you confused on the Joomla side of things or the Akeeba Subscriptions side of things?
Have you checked out Akeeba Subscriptions' documentation?
www.akeebabackup.com/documentation/akeeba-subscriptions.html Steps to using Akeeba Subscriptions:
1) Basically, the first thing you should do when you install Akeeba Subscriptions is configure the global options (top right within the Akeeba Subscriptions dashboard). Set up your currency and your front-end display options.
2) Next, set up a subscription level from the "Subscription Levels" area. Do this for as many subscription levels as you need.
3) Go to plugin manager and search for "Akeeba Subscriptions Payment - Paypal" and configure all your merchant information on the right side.
4) Finally, create the menu item. Go to your menu in menu manager and create a new menu item. Set its type to Akeeba Subscriptions >> All Levels (Awesome layout).
That's it! :)
Let us know if you have any questions or get stuck at any part.
Kind regards,
Nick