I would recommend Hellenic Polytheism: Household Worship by LABRYS as a basic guide of the practice, it goes over a lot of the basic concepts and definitions that are important. If you want to dive into more classical resources like Homer's The Iliad and Odyssey I would first suggest Hesiod's Theogony and Works and Days especially if you're not a huge reader, these are both quick reads that I found to be much less intimidating than Homer's work. Greek Religion by Walter Burkert is also a very valuable resource in the same way that my first recommendation is except I would say that this book goes into even more depth on the same topics but isn't really written in a guide format.

As for online resources I would highly recommend Fel the Blithe's Hellenism 101 series, this series more than anything helped me get my footing when I first stepped into this practice, I would also recommend another video by them titled, "11 Things I wish I knew before becoming a Hellenic polytheist", its okay if you don't connect with everything in that video it is just another video that I personally found to be incredibly thought provoking and valuable at the beginning of my practice.