Yes, what Egon sent is basically it, however there are some specific options, such as if somebody knows French, there is an Assimil course for Ancient Greek in French, Assimil courses are very good for language learning.
AG is a pretty hard language to learn, it's far away from English or Finnish, the books are also not the most entertaining, there is no options such as watching TV shows as with living languages. There are some graded reader books in that collection (basically all graded reader for AG is there) and some of them tells a story, these are the better books like Greek boy at home. Still not peak entertainment. There are also Grammar translation books there, which is usually the worsts, however the athenaze series stands out, I found it pretty good.
For these reason some may learn Greek first because because it's the closest living language to AG, about 50% similar.