How to change engine belts/?

It would help to know what car and what type of belts. They aren't all the same.How to change engine belts/?If you have to ask, you had better let a mechanic do it.How to change engine belts/?kinda hard to explain... but just stick a wrench on the tensioner and loosen the belt and throw a new one on there, make sure it is routed exactly the same as the original