My first advice is to read all of the general books on ancient coins that you can find.
A large public library is a good palce to start.
Most people start with the collecting of the coins of ancient Rome. That is not surprising, because the legends are the easiest to understand.
Like yourself, my first ancient Greek coin was one of which I knew very little about. That aroused my curiousity, and I wanted to find out about it.
I picked up a book from the local library on ancient Greek history and read it, then a book on Greek mythology, to understand something of the imagery on Greek coins.
I next bought a book by Charles Seltman on Greek coins, and read that thouroughly, then I bought the double volume of Greek Coins and Their Values by David Sear. All three books make an excellent permanent reference.
For current prices on Greek coins available for sale, VCOINS is an excellent site.
Much later, I bought an excellent book on coin forgery by Charles M. Larson, to protect myself, and I also acquired a reasonable reference collection of fake ancient coins to learn how to much more easily spot fake coins. Much less of a worry in this area, if you buy off a dealer, of the highest reputation; their business depends on, and has been built on honesty.
If I am considering the acquisition of a Greek coin, I will refer to Sear's books and VCOINS, for a near equivalent coin that may be for sale, before making up my mind to buy, or make a bid at auction.
In the long run, lots of ancient coin collectors end up liking ancient Greek coins more than other areas of ancient coin collecting. I think that is the result of the (mostly) beautiful, and more varied artwork to be found on ancient Greek coins. It just takes more time to fully appreciate Greek coins than Roman coins, because they are harder to understand.
You made a very good first purchase. Congratulations!
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By the way,

to the world of ancient coin collecting. The most experienced collectors jokingly refer to ancient coin collecting as a disease.