Hi Blaggy!!
Congrats on Your CX-12, I hope You grow a liking to it and enjoy playing a Lot. The CX-12 has got Lots of reviews here and seems to be a Great choice.
Well, I just thought I'd put some "General information" here; You say You read music so there isn't much for You to learn that way, all You need to know is how to "translate" Your knowledge to the harmonica. There are some tips here already about the lay-out, blow and draw notes etcetera, Hopefully I can add some useful information here for You:
The Biggest difference in playing a chromatic harmonica that You need to remember is that there are No Flats on a Chromatic. For Any Flattened note, You will need to play what's called "the Enharmonic", so: Instead of a B-Flat, You play the A-Sharp. Not so much of a problem with this note as A and B are both Draw-notes, but it can be confusing anywhere else: an E-Flat can Only be played as a D-Sharp, and the E is a Blow but the D is a Draw.
I personally reckon that once You get Your head around this, You will soon get the Whole Concept of how to play a Chromatic harmonica.
It's nothing special or anything Secretive, but it's just that sort of Mind-Set that helps a Lot IMO.
Have Fun with Your chromatic!!!