Carbon Arrow University is a series of informative articles posted on the www.huntersfriend.com website.
Using the natural physical laws, these articles discuss everything you need to know about the science of arrow flight and determining the right arrow for your bow.
Read the series, or pick individual subjects that are giving you trouble:
I don’t necessarily follow everything the series extols (ex. I use a heavier broadhead and insert than is recommended), but it is a fantastic resource nonetheless.