change email problem

I saw a forum post about having to have your halo waypoint email the same as your xbox live email. Mine are different. I want to change my halo way point email to match my xbox’s one, or else according to another post, the beta wont show up in my xbox insider hub app. If some one could list steps to where to change that on the web site, that would be great, since I cannot find it on the site or in support… Thanks.