Cannot play Halo: Reach

I changed my GT on Xbox1 and then could not play Halo: Reach. I’ve seen other people have had this issue. Following another users advice, I deleted my 360 storage from my X1, with the intention of re-downloading my 360 profile.

And here’s my issue: I can’t seem to download my 360 profile. The reason being, I have no idea how to.

SOMEBODY. HELP.

When you start up an Xbox 360 game press both of the buttons underneath the home button to bring up the Xbox 360 menu and from there you can re-download your profile.