This site has SO MUCH information! I'm just leaving the link here and you can spend hours exploring!!
https://nchfp.uga.edu/how/can7_jam_jelly.html
Includes:Recipes and Information on:
Types of Jellied Products
Jellied Product Ingredients
Extracting Juice for Jelly
General Information on Canning Jams, Jellies, and Marmalades
Making Jelly without added Pectin
Making Jam without added Pectin
Making Jams and Jellies with added Pectin
Processing Jams and Jellies
Steps in Processing Jams and Jellies
Testing Jelly without Added Pectin
Remaking Soft Jellies
Stiff Jams or Jellies
Storing Home-Canned Jams and Jellies
Causes and Possible Solutions for Problems with Jellied Fruit Products