Get a book for each of the powders and bullets you'll be using. Most of these companies have data online now.

I like to seat close to lands and work back until I find a sweet spot. As for powder Hodgdon, IMR, Ramshot, and Reloader are the most common with several different offerings. You'll have to play with them to find the best one. On primers, I like the CCI BR2 but Winchester WLR and Rem 9 1/2 work well.

Just be patient on the hording and panic buying of supplies. It will all settle down after a while.