The link below is a great overview for making jam.

National Center for Home Preservation

Quite simply, add about 3 cups of cleaned and chopped (if needed) fruit to a saucepan with about 1/2 cup sugar. Bring gently to a boil and cook over medium heat until the fruit is soft or the berries have popped.  Run the fruit through a sieve to remove skins (if desired).  Return to the sauce pan and adjust sugar.  Bring to a boil and then simmer until a candy/jelly thermometer reads 220 degrees.  Pour into a sterilized container and refrigerate.  If you are keeping the jam in the refrigerator, you do not have to process in a water bath.

Makes about 1 cup