Nintendo 3ds XL hinge won’t lock, too loose when closing and opening

Hi all, so I am doing my second repair ever, and my first repair on something like this. (Just so you guys know how you can explain to me haha) and for this task, I needed to replace the front housing since the right hinge was completely gone, I don’t know if any other pieces went missing when that hinge was destroyed (I purchased this 3ds xl broken like how it was and the previous owner doesn’t know anything about it since he found it broken.) The only piece I have is the hinge, so I don’t know what’s going on. I put the whole thing together and whenever I lifted it up, top screen just flips down with no effort. Help would be much appreciated!!!