Try finding an online tutorial, but don't be afraid to ask a friend for help — if you're fortunate enough to have one that knows Erlang. The core language isn't too bad if you're familiar with FP, but the associated concepts like gen_*, supervision hierarchies, and error handling are tricky. Don't be ashamed to ask for help … it's not as straightforward as most of the languages you've learned.
Implement the things you're learning. After you learn a concept, try building something that uses that concept. If nothing comes to mind, ask someone for an assignment or find a tutorial with homework. Reading tutorials and manuals will tell you how a feature works, but you won't really understand where it's appropriate to use until you've actually used it incorrectly a few times. Experience is key; you'll probably find that after a while of programming Erlang that everything you wrote more than two weeks ago is complete crap.
Once you get into the real world use http://erldocs.com for reference. It's the same material as http://www.erlang.org/doc but presented better.