For Latin, the go to resource to start learning is the book Lingua Latina [1] which has an easy conversational style. You can understand a good percentage of the book without any a priori (see what i did there? :) ) knowledge of any kind. Concurrently with that, you might listen to the Latin language videos by Scorpio Martianus [2] who also does some videos in Greek.

[1] https://books.google.com/books/about/Familia_Romana.html?id=...

[2] https://www.youtube.com/channel/UCRllohBcHec7YUgW6HfltLA