Add just enough water to cover the apple (not too much or else you'll spend ages boiling it off). Bring to boil and then add 1 kg sugar (same weight as apples). Stir and wait for the setting point to be reached (when a skin forms on the surface or on a sample taken from the pan). Then put into warm jars.
You should aim for this to be quite chunky so don't chop the apple too finely.
We made 8 jars on Sunday. This is something mainly to be used with meat, especially lamb. It's great with lamb bangers or burgers.