Helmets that require Halo Waypoint

Everyone knows that they can get some cool things if they sign into Halo Waypoint. What I am confused about is how that is done. When do they become avilable to you? I signed up for this, so can I purchase them? A little new to how the system works.

Pretty much it tracks your progress throughout all halo games on xbox 360. You can get the helmets through achievements and milestones. Milestones are based on how many achievements you currently have. So pretty much after you fill the requirements for said helmet (you can see them by highlighting the armor piece and pressing A) just simpley return to reach and the armor is unlocked

I’m sure there will be more done with the Waypoint game once the TU is out(maybe more armor unlocked from there), CEA is released and Halo 4 comes. Unlockables are obvious ideas but some innovation is needed.