First, let's not get ahead of ourselves by thinking about breeding at this point. Let's just get your husbandry skills up to speed.
How you set up an enclosure depends on the type of frog selected. Treefrogs require good ventilation and taller cages than most other frogs. Typical Ranids, such as American bullfrogs and leopard frogs will require large semi-aquatic enclosures, as they are skittish and have powerful jumping legs. Fire-bellied toads will require similar enclosures, but on a smaller scale. True toads, Pac-man frogs, and tomato frogs are terrestrial, so most of them will do fine with a standard 10-gallon tank. Clawed frogs and Suriname toads are totally aquatic, so they can be kept like fish. Poison dart frogs and mantellas can be set up in enclosed greenhouse-type terrariums, but these frogs are considered too advanced for the beginner.
Do not mix amphibian species. There a few reasons for this. Most amphibians produce skin secretions that can be toxic, while at the same time they have porous skin that absorbs moisture, pollutants, and toxins. So mixing species will cause them to poison each other, or as it is often referred to as cross-contamination. Most frogs offered for sale are wild-caught and are usually carrying gastrointestinal parasites and other pathogens that are native to where they were collected. So mixing frogs from different lands is to cross-infect your frogs with pathogens that they may not have any immunity to. Captive bred frogs are sometimes introduced to these as well in pet shops and similar situations, so mixing them would be the same deal. There are a few more reasons, but those can wait.
So there you have some basic protocols in frog husbandry.