Once logged in the forum, if you go to the forum homepage you'll see a green circle with a small tick in it. If you click that for the forum categories you'd like to subscribe to it'll be added to your subscription list which you can edit and track via your subscription list (which you can get to via clicking the 'quick links' link in the dark blue main menu at the top of the forum).

Then, when a new topic is created you'll be notified via email (if you have that option turned on) or when you visit your subscription page.

Threads you're already involved in, or threads you've created, will often be added to your subscription list automatically, though subscribing to a whole forum category will always let you know what's going on.

Some forum categories I'm subscribed to are the Introductions forum, the Tools and Equipment forum, the Training and NVQ's forum, and the Tiling forum.

You can add and remove subscribed forum categories at any point.

Feel free to give it a go.