Work at a coin store, first time with ancient coins, help needed.

Hello everybody! I am currently working at a coin store and I’ve elected to take on my next project for learning ancient coins enough to buy to and sell fairly, but I’ve realized this task may have been a bit too much for a one time learning opportunity. I am wondering what the best resources are for identifying ancient coinage, and how to price them. I am also wondering how often, if at all, I would be allowed to ask this subreddit for help with identification/pictures. I do not wish to do any buying or selling on this subreddit, but I want to be fair to all parties.

I took up this task largely because the only person who knew how to buy them fairly and sell them fairly in this store l passed away recently, and I’ve been wanting to learn for some time now.

Thank you very much for any information!