Getting started with Myo development is easy!
You can start by purchasing a Myo Gesture Control Armband here and then visiting the Myo Developer Portal for information on how to develop for the Myo armband. The Developer Portal is your primary resource as a Myo developer. The portal will give you access to the Software Development Kit (SDK), all the necessary documentation and the forums
If you're looking for an introduction to some lightweight coding, take a look at Myo Scripts.
If you need help with creating your Myo project or simply want to find like-minded individuals, be sure to check out the Myo Developer Forum and post any questions you have.