It isn't complicated at all; just need oranges, water and sugar. However, as you need to boil it up rapidly there's a risk of it boiling over; this is where a jam pan is worth having. I have made jams in a pressure cooker before but you can only fill it at the most half way up, if not it boils over. After a while setting point is reached, you can test this by putting a bit of the marmelade (without the bits) on a cold saucer and if a skin forms (it wrinkles) on the surface when you push it with your fingernail, it's ready to be put into clean, warm, dry jam jars. La voilà!