Overlaping and disabling animations help

So im creating some animations for a commissioner and i have some pretty great animations that i have made for them. but When i asked if they liked the animation they ask if i could disable the legs so the original Roblox walking animation would overlap the animation i made. I tried to delete the legs to see if that worked, but i just slid around the Baseplate. I use the given animated tools that roblox provide in studios.

(they want me to disable the legs of the animation to put original roblox run animation
so it overlaps my animation)