Let me reassure you a little. While you may have bought a cheaper trailer (Nothing wrong with that), a large majority of the trailers are built the same way when it comes to roof construction. Most have one of two types of rubber or membrane roof that are glued to ply or fiber board roofing and sealed around the edges with trim and dicor self leveling sealant along with the cutouts for AC's, Antenna's, vent stacks for plumbing and refrigerators, etc being sealed.
Water intrusion is the thing that kills most RV's. Doing regular roof inspections is the (in my opinion) the most important part of RV maintenance. AT least quarterly, I get on my roof and inspect the sealant, looking for places the sealant has cracked or come up from the rubber roof and fixing those area's.
Takes less than 15-20 minutes to do a full roof inspection and add in another 15-20 minutes to do most resealing jobs.
Also check your corners of the trailer, windows, doors, etc. Anyplace the solid walls, front or back of the trailer has been cut (for plugs, doors, windows, connection fittings, etc) or ends.
Here are a couple videos to help you understand what is required in a roof inspection. As I mentioned, don't think it's just the roof. Check all seams, edges and intrusions into the 4 walls as well.
Relax and enjoy your Puma. Roof damage isn't specific to one make or model. It's usually specific to someone that didn't do enough to prevent it.