Summarize the following:
The more you chop them, the easier the jam will be to spread. Put it on a burner and turn it to high heat. These standard packages are available at kitchen/canning shops or online. Stir well to combine. Lemon juice contains extra pectin and adds flavor. Also, add one-fourth cup (59ml) of rum or alcohol of your choice if you want a little extra flavor. Bring it to a full boil. Turn it to medium heat. Traditional cherry jam is sweet, so five cups of granulated sugar is added for four cups of cherries. However, you can add as little as three cups of sugar for a tarter, healthier jam. Let it boil for one minute. Remove it from heat.

Summary:
Chop the cherries or grind them in a food mill. Pour four cups of cherries into a large metal stockpot or metal Dutch oven. Shake your package of powdered fruit pectin into the pot. Add the lemon juice. Stir the mixture. Stir in your sugar. Return the mixture to a boil.