Hi, I am no keyboard player but had a few piano lessons a long time ago. Suggest you check out youtube, that is where I get a lot of cool ‘lessons’ and how to’s. Try searching for how to play keyboards or piano for a particular song as well as searching for melodica on youtube.
There are also a few apps on android and itunes too I would imagine for how to play keyboards or piano. Before too long you will be sounding songs out and playing by ear. Music theory is great but I tend to learn tunes faster trying to play them by ear.
Matt, I should add that using your ear is very important but theory is just as important, it is good to know both it will make you that much better a player.
Good luck we are here to help.
Monsters of Melodica
Yes Melodica Me, quite correct! I am learning music theory now, I just wish I had applied myself earlier on to it
Sorry to hear about the unpleasant experience playing harmonica Matt. Sedel make some wonderful harmonica with plastic resin combs you might want to try? I use the Sedel D and G in Paddy Richter tuning the Blues Session model tuned for Irish Traditional music. Very nice and affordable too.