Belt insatll on the 100

Alright, I have the side belts on, but when looking at the x-belt, I do not have enough of m5-8 button. I have looked and none are on the floor. When securing thee y-belt, I used and m5-8 button to secure to sliding nut inside and one to the back. Does the x-belt get done at a later step or did I miss something

Hi John
I found the same thing when I installed my belts. I just bought a few more from the hardware.

I called inventables, and was told that the back screw is optional. I kind of like having it secured back there. Anyway, going to remove the 2 in the back and continue the build. I think i will remove the post assembly screw and nut.