Starting out with Retool

Hi folks im looking at starting to use retool to create a ledger system, a simple one and a training record system out of google sheets. Is it a difficult thing to get into or is it quite good. I have quite a bit of time so no problem there. I would like to start from the beginning. Im not very familiar with sql so things like summing columns etc I would maybe struggle. Any advice is greatly received.
Thanks again.

@alanfallow Welcome to the forum! Your best bet is to start with tutorials here