How do I slide the cover back on my case

prebuilt case

Describe your problem. List any error messages and symptoms. Be descriptive.

I am an idiot and I can't put the side of my case back on List anything you've done in attempt to diagnose or fix the problem.

tried sliding it back in place, didn't work. Post relevant photos of build/parts here.

https://imgur.com/a/uBi2I