I'll play a game with my kids sometimes, but I generally don't have the time or inclination anymore. Every once in a while, I might play something though...
to roblox and make a script NOT LOCAL SCRIPT if you do a local script only the player will see it and no one else, put in the normal script the mesh (knife) tool and then make a UI and just do it so when the UI is pressed the mesh.texture changes into your skin (texture) ID...