Good day,

I am trying to do something with the subscriptions but I can't see how to do it.

Is it possible to create a subscription with renewals that will grant members access to a specific forum or forums? Or even downloading files?

I've created a test subscription but I cant see any option to do that when creating/editing it. 

Thanks a lot

The only way to do this is create a usergroup that has access to the forum(s) and download(s). Create a subscription and have the user moved to that usergroup upon purchase.

Indeed what Alex says above is the correct way to go about this. The only way in which to give access to a member is through the group based permissions system