Grate some lemon peel and throw the lemon also into the pot, its a good idea to cut the lemon before in slices.
Then throw the plums together with the jam sugar in a saucepan and bring to a boil. Stir this stew good. Just before the jam is cooking, add some grated cinnamon, lemon peel, lemon juice, vanilla, and add a little bit red wine. You can use a "heavy" wine.
So, all this must biol ca 4 to 5 minutes. The plums must separate from their stones, - you don't want to eat stone right? Then your just have to pour it all through a sieve. There is a lot of juice if the plums are very ripe. Don't throw this juice away, because its a good syrup and you can store it quite long in your fridge to use it as a drink. Just dilute this syrup with water and you have a nice refreshing drink. The factories are doing the same, but this way you don't have to buy it.
Anyway, its clear, now you squeeze all these cooked & drained plums with a large spoon through the sieve into a bowl. Now you only have to fill the "mud" immediately into prepared jars, preferably you use boiling water to sterilize them before, so the jam does not get funny after some month.