A few days ago I got in, shut the door and it went BANG, and bounced back open

.
Apparently a little spring inside the latch assy musta broke, I took it off but can't figure out for the life of me how to get it apart

.
Does anyone know where I can buy a new one? Or better yet, how to get it apart and fix it myself?
Someone already robbed it off my parts bunny

......years ago.
If it's nla I'll try a jy.
thanks