How do you script that , I don't even know where to start .
Is there anything that can help me to understand how to make it ?
Thanks for the Help !
You could start by making invisible ladder-like outdents on the walls you want to be walkable. Now, the basic Robloxian can CLIMB across. In first person, just manipulating the camera angle with a script (look up 'Camera Manipulation Roblox' for more details) will make it feel like wall-walking, but you'll need to replace the climbing animation to make it look that way to other users.
So there you have it. Wall-walking may be hard to script but with a few lines of code wall-CLIMBING can feel a hell of a lot easier to manipulate.
Why start from scratch when you can just modify a ROBLOX default system?