Easily answered, possibly.

If the person's adobe id (email address) is the same as his enTourage account email address, then in the Registration Wizard you indicate that the Adobe ID is the same as the enTourage info. This includes if the person has never purchased an ebook, or set up an account at www.adobe.com for any adobe product.

If the person's adobe id is different from the enTourage email, or the adobe password is different from the enTourage password, then in the Registration Wizard he must indicate it's different and then specify the email and password. If he's forgotten the password, he should go to www.adobe.com and click "Sign In" in the top right corner, and then follow the "forgot password" process. Once the adobe password has been settled, he can retry the Registration Wizard.

enTourage and Adobe don't have a relationship regarding DRM. The DRM is 100% adobe's and adobe's alone. (It is in fact possible for Adobe to register the eDGe without involving enTourage.)

EDIT: Also see https://www.entourageedge.com/suppor...kbarticleid=86.