how do i make a soundboard with a stop all sounds button ?

hi, i have 3 questions i really hope they can be answerd

# 1 How do i make a soundboard

# 2 How do i make a back round for a soundboard

# 3 How do i make a stop all sounds button i think it is called a "sas " button thats what i have seen on soundboards.

so please help me with these questions and im gonna make a soundboard thank you..............................................