It's not terribly difficult...but like a lot of cooking, the outcome is dependent on the fruit you are using,its sugar content,the temperature you are cooking at, etc.
If I can do it,anybody can ;-)
Choose plums/greengage/damsons. Easy but time consuming stirring for hours. Berries need added pectin.
1.Equal weight of fruit to sugar
2.Remove pips & tie in cloth
3. Fruit/sugar/pips in pan & cover with just enuf water to stew
4. Bring to boil, simmer & stir for 1+ hours
5.To test, drip on plate to check consistency
Mmmm had home made marmslade at my mums this weekend, it wad gorg, she gave me a jar of spicy plum chutney as well but not sure about it, i can't figure out if it on the banned list or not
Years ago I had a Victoria plum tree...so made masses of jam several years running. Added spices-cloves and cinnamon to a few batches.
Also collected blackberries from the roadside and made jam from them
I'd like to try store bought strawberries...but I've given up sugar. ;-(