This FAQ answer the question "How to get started with Codenvy?"

Codenvy: Get Started

When you sign up for Codenvy, you should already have a github.com account and you want to choose your github account to Login with.

Authorizing OAuth2: This allows Codenvy to clone from and push to Github.com

When you "push" to get be sure to check the "Push committed changes" checkbox

Directions to enter Username and Email

Adding Username and Email