Question Old pc case

[1L3NKAS]

So im upgrading my pc a little bit and i had to give it to my uncle to fix something, my case is pretty much almost broken so i wanted to open it and he fixed something, i cant open it, can someone tell me how do i open pc case that has opening like this? Any help would be appreciated Here's the photo

 

[1L3NKAS]

Update: i unfolded it and thats what i had to do