How to breed hamsters or guinea pigs

Are you willing to keep all the babies that you can not sell, if not then do not bother breeding

We used to breed hamsters.
You just put the female in the cage with the male and in about 3 weeks you will have babies.
Just make sure the female has her own cage. She will make a nest for them out of the bedding. That is how you know she is about to have them. She will have about 20 babies. Yes, 20.
We had her in a glass aquarium on top of a clear glass table and we would lay under the table and watch them feed from under the nest. It was so intersting.

all you really have to do is put them together. Their gestation period is short. Why do not you look it up or buy a book?