Ripe fruit trees practically stone us with their bounty. If you own any your feet must be sore. Plums, peaches, apricots. Before they are ready for picking, you better be ready for jamming.
My childhood friend owns about a dozen trees that produce summer and fall fruit. She shops and stock piles large quantities of sugar, glass canning jars, brand new lids every single time she cans, extra large stock pots, canning tongs, funnels, ladles, etc. She sterilizes the jars ahead of time, and checks the ripeness of fruit every day. Usually the whole tree or multiple trees are all ripe at once. Therefore, be ready to cook the fruit over a hot stove, along with boiling the lids and jars separately in other pots, bellowing the steam into your face on a hot summer's day!
After picking a peck, wash, cut in half, and pit the fruit. In days of yore, fruit was actually peeled, but now we all know all the fiber and nutrition lies in the skin. Another faster method of separating the pits is to wash whole fruit and cook them 10-15 minutes in a stock pot with just 1/2 cup water. Remove from heat and let cool an hour or two. Then gently smash down with a potato masher, eventually digging down with your hands plucking the pits out by handfuls.
Recipes for jam, and jellies are included in the Certo brand box of pectin. 4-6 cups of pitted fruit will require 7-8 cups of sugar! There is no doubling up on ingredients. One batch at a time, no matter how much fruit you have. However, there is a freezer jam option included by Certo in case you run out of canning jars, time, or stamina. All of this my sister form another Mr. described to me as she handed me her golden jars of peach and apricot preserves.