I signed up for everything so will i just get a email saying i have been accepted in or do i have to do something else
Just a case of waiting now. Once flighting is about to start for Halo 4 invites will be sent out to those who are signed up and opted in. There's no guarantee you'll be invited though
You'll probably have to wait until middle of October when Halo 4 is predicted to flight. In the meantime just keep your profile up to date and any time you upgrade your PC hardware or something be sure to update your DxDiag log.