Prunes=plums, Figs=Figs, usually dried.
Most of the prunes available now have been coated in oil unfortunately. If you can find them without oil then even better.
Just warm them up in water on the stove, to start to rehydrate them, then strain them, it softens them. Add them to custard.
We mostly eat them out of hand. We use them in fruitcake too, either snipped into smaller pieces, or blended with a little water to make a paste and add that to the cake portion of fruitcake. They are tangy sweet and delicious.