How do I Open the back of a ZTE Blade V9?

Hello!

I recently treated my phone quite badly and it resulted in a cracked screen a a partially broken LCD. Thats why im trying to repair it myself. Ive got most of it figured out except for the actual , opening of the phone part.

There are no visible screws I can access from the outside and im quite confused. I’ve seen a spanish video of someone I guess.. “cutting “ the back open very precisely with a Razor but im sure there has to be a different way!

Please help me!