Each year, during harvest we get into a seed-saving mode. I set aside the first and best of everything that we grow to save seeds. Taking the first and best helps make my chances at having a good viable supply of garden seed for next year.
We have tables with seeds laid out on them to dry. Above are some black beans, which we dry and store for use all year long in soups. Before putting them in the pantry, we take enough seed out to plant again next year.
Learning

How did I learn about seed-saving? I got a good book (Goodwill) entitled, “Seed to Seed, Seed Saving and Growing Techniques for Vegetable Gardeners” by Suzanne Ashworth. It is a reference that I use over and over. Her detailed explanations and pictures taught me what I needed to know. I realize, not everyone wants to use a paper book with pages. So, look online for a reference that you would like to use. After a quick search, here is one from the University of Minnesota.
Here are some chokecherry berries drying after being cleaned. They need a cheesecloth stretched over them to keep the birds out of them. No seed saving is required this year. After, the berries dry, I place them in plastic bags to freeze. They make wonderful jam all winter long.
Most people know how corn is processed. I shuck it, and lay it out to dry on a table out of the sun. Rubbing the seeds off finishes the process. We save dried corn for soup and put some seeds in the box for next year.
Hope you are able to get a good reference book for yourself to learn these techniques. Saving your own seeds is really worth the effort.