There is no set way to go about it.

Just make sure that they are trust worthy and that everything is totally clear and upfront.

Put it in writing!

Usually the female goes to the male.
Unless the owner of the male has no plans for him for that season, and he is being loaned out to breed multiple females.

50/50 split with the owner of the male getting first pick is common, but again it depends on the animals values and what the pre arrangement is.