Hi there
First off, welcome to the forum! if you are going to keep Aquatic frogs make sure to identify them first because once they start to grow, large will eat small! its most likely that your frogs are either African dwarf frogs or African Clawed frogs. African clawed frogs have large bodies with bulging eyes on the top of their head, webbed legs and are usually sold as an albino frog and will get around 5 inches or more. African dwarf frogs on the other hand are much smaller and only grow to 1.5 inches, these guys are brown or grey and have webbing on all limbs, they have eyes on the sides of their head and have a slightly upturned snout.
Maintain the frogs like you would a fish with proper Ph testing and cycling the aquarium, about four ADFs can be housed in a five gallon and one adult ACF can be housed in a 20 gallon. the ACFs will eat tubiflex worms, nightcrawlers and specialized food for aquatic fogs. ADFs will eat bloodworms and small pelleted food called frogbites, Many people say that you will not need a water heater for either animals but i put one in so the water is not ice cold, Provide plenty of hiding spaces and a substrate of gravel for ADFs and sand or a bare bottom for ACFs. it is important that you know that if you are housing ADFs with tropicl fish, the frog may be outcompeted for food, i feed the frogs with large feeding tongs for handling prey items, and ACFs will eat other fish if they have the chance.
Hope you have good luck with your frogs!
references
~ Frogs toads and tree frogs Barlett and Barlett
~ Frogs and toads Devin Edmonds
~ Aquariumforums