Best Advice suggestion 7.1

Hi Everyone,

I am new to the whole home theater space - i moved to a new house and at which i inherited a home theater system. It has 7 speakers in wall - 3 front and 4 rear. The current receiver I have for it is a Yamaha TSR-7850. Now here comes my dilemma - the cables that go to the receiver are not labeled. What is the best way to test where each speaker goes? Any help would be greatly appreciated. Id like to avoid paying for a service to come out and do it for me.

Thank you!