Are you serious? Why would you attempt changing sparks when you don't know
where they are.
There's a lot more to changing them, than just finding them.
You can damage the engine if you change them hot for example, or you'll get
an awful gas mileage if you gap them improperly.
I'd let a professional do it if you car has a V6. Otherwise it should be
simple, and plugs should be right in front of your block.