Hi there - I'm also a beginner on the Anglo, just been learning for about three months now and am completely hooked! Like you, having previously played piano, I was a bit discombobulated by the layout of notes on the Anglo, but I also rather relished the challenge of learning to play something so different. As recommended above by Leah, I'm just learning the notes gradually as they crop up in tunes - and it's amazing how many great tunes you can play with just a few notes! I decided to get some online tuition and I'm doing the beginners' starter course with irishconcertinalessons.com (Caitlin Nic Gabhann). I'm finding that it's a really fantastic course that gets you playing loads of traditional Irish tunes really quickly. The Online Academy of Irish Music also has some courses and I think it offers a 14-day free trial. Personally, I've found it extremely helpful to get some guidance from an experienced player. Good luck with your new concertina - enjoy!
