Hello, I just got a giant african bullfrog a few months ago. This is my first frog!

I've been getting WAY too much conflicting advice on feeding, so can someone please explain it to me as simple as possible? Right now my frog is about 3 months old and eats about 8-10 crickets every night.
So my questions are:
-what should they eat and how much at each age mark or size? (I was told only crickets until it's a juvie)
-What are they best staples for babies, juvies, and adults?
-how much is under-feeding?
-How do you know if you're over-feeding?

All the information is so over-whelming haha. So can someone please simplify it for me? thanks!