Reason has everything you'll ever need, honestly. Get as familiar as possible with Thor, Malstrom, Subtractor, etc. as you can. Thor, especially combined with any of the incredible effects Reason provides, has just as much versatility as any of the bigger plugins people talk about a lot (like Massive or Spire). In addition, the Kong drum machine is an unbelievably powerful tool when it comes to editing, programming and modifying drum samples. Experiment with all these instruments and just have fun before you start really looking into tutorials or manuals or trying to understand what's happening on a technical level.
My favorite thing about Reason is that it forces you to work with the tools provided--trying to decide which plugin to get is never a problem, since you CAN'T get any other plugins. lol. Plus, limitations tend to inspire creativity
I think the most important thing to keep in mind as a beginner is that there's no correct way of doing anything; experiment and fuck around as much or as little as you want to, and don't feel pressured into working in a specific way just because that's how someone else does it.
Oh and don't worry if the first 10, 50, 100, 150, 200 things you make aren't to your liking--just keep at it and you'll be happy with the results eventually