Go to http://canningusa.com/ There’s tons of info there. I have an All American 16 quart canner.. love this baby. No gaskets and will last a thousand years. Don’t bother with Presto or others with rubber gaskets. I have been canning for years and it’s the best way to preserve food. No electricity required as in a freezer. Good luck. You will love the hobby.
When I was stationed in Panama we were catching craploads of yellowfin tuna and just had a tiny freezer (frozen tuna sux anyway) and so I learned to can tuna. Mom and granny canned peaches and tomatoes but I gotta say, canned meat is the Holy Grail. Fantastic flavor and I will say that I love Sashimi but my canned tuna tastes better.