Risa, if "water is pouring out of the tub spout when its all shut off" as you said then that plumber you spoke too is wrong and replacing the spout is a waste of time!
I have also explained what the valve is and how to disassemble it in the other thread:
https://www.askmehelpdesk.com/plumbi...ew-565332.html
If you can't understand the instructions as provided then I would suggest that you call in a plumber (not the one that suggested replacing the spout). If you cannot afford a plumber AND you cannot understand my instructions well then, I simply don't know what to tell you! I would suggest getting help from a friend!
PS: The "VALVE" is the the thing that the handle is attached to! Reread that other thread...;)
Mark