COMPLETELY new to this

[Mentat]

Hello and welcome to FF! Are the frogs front extremities webbed or non-webbed? Asking to figure out if ADF or ACF.

You can feed them prepared food (aquatic frog food), thawed frozen food (bloodworms, daphnia, etc.), or live (i.e. black worms). The main thing is that you do not overfeed them since uneaten food will rapidly degrade aquarium water.

For couple 1 in. frogs would try to replace 50% daily with same temperature water. Do use a good dechlorinator like Seachem Prime to remove chloramines, heavy metals, and other bad stuff. A cycled tank is extremely beneficial to aquariums since the present bacteria colony will automatically degrade bad Ammonia to less bad Nitrites and then to almost not bad Nitrates. Those then get removed with weekly water changes.

In the case of aquatic frogs that prefer little to no water movement and could actually drown in a strong current (big powerful filter + small tank combo) you have to match filter and tank; but that is easy to do. With smaller tanks you can use sponge filters which come in various sizes. Can run those with a small air pump and just need to rinse them (in tank water you remove during water change) once a week. Cycling will take around 4 weeks; but can reduce that in half if use a product like Seachem Stability. During that time can continue to do daily water changes and do not add any chemicals or products that reduce or sequester Ammonia (i.e. Amquel).
Hope this answers your questions and good luck !