Just to add to the useful advice already given
Take a look at realseeds website, loads of useful info and even free plans for a threshing/winnowing machine if you plan to do a lot.
As for books, one of my favourites is ‘The Seed Saver’s Handbook’, by J Cherfas , M & J Fanton. It’s out of print but often pops up on used book sites.
Hope this helps,
Tristan
Tristan