Welcome to FF Chooky! Don't know ID of frog, but will try to help and maybe others members from Australia can pitch in too. Can't recommend tank size without knowing species, but in general you want a taller than longer enclosure for tree frogs and the opposite for ground frogs. Unless aquatic (full or 2/3rds water set-up); a water dish with dechlorinated water to frogs chin level will do for frog's soaking.

I would try and find out the weather characteristics of area where you got them at internet weather page and then simulate that by matching temp and humidity in enclosure, will need temperature and humidity gauges to monitor set-up. Also, cover back and sides of enclosure so they feel secure. If tree frogs will need branches and vines to climb, with shrubbery to hide.

For food gut loaded crickets (sized distance between frogs eyes) or similar should do for tree frogs and if ground frog can also feed earthworms (cut to size) too. When babies and juveniles would feed daily. Once grown can space that out every other day as growth slows and then every couple days for fully grown adults. The amount would be all frog will eat in 10-15 minutes or to satiation. Should get calcium and vitamin supplements (recommend Repashy or Repto Cal) and dust food weekly with CA 2x and vitamins 1x on different days and with skip day between dustings. Once frogs are grown can cut that in half. If you visit the forum's Care Article section (Frog Forum - Care Articles) will see more detailed descriptions of care articles and it's a question of finding one that closely fits your frogs. Good luck !