Desks can be really hard to put together! I had one, a long time ago, that I had put together myself (and I was *so* proud of that!) I used it for YEARS.
One day, the boyfriend was staring at it... and I asked what was going on.
Apparently, he had just noticed that I put the hinge (for a cabinet-type door) on totally inside out (?). Like, completely wrong. Somehow, the thing worked. I'm still not sure what was wrong, as I don't have very good spatial skills... it bugged him though, so he fixed it.
Good luck getting all your stuff together and working! Hope you find the parts you need and the rest goes smoothly!