Welcome! I feel the absolute best way to learn is by getting one of the very good books on the subject, go thru the tutorials, and learn by doing. Along the way you will find things you want to incorporate into you database, and you will learn FileMaker inside and out. Design, building and tweaking your database will go much smoother and quicker. I couldn't resist jumping in, and ended up rebuilding my database (twice). Although I appreciate the learning experience, it was frustrating. Slow and steady are best.
Once you get going with your database, it will be much easier & quicker to get help here
My 2 favorite books:
FileMaker Pro (your version): The Missing Manual
The FileMaker Training Series.(For FileMaker 12)
The hands-down best video training (once again, just my opinion) is by Mark John Osborne:
I'm still not thru it after a few months (never have the time), but you will learn every aspect of FileMaker as you build a Contacts Database, then build and merge with an Invoicing Solution. I think its something like 45-50 hours of training.
Also, when you can, start with todays posts and work your ways backwards--so much info from everyone, especially the mind & files of PhilModJunk.