I have two bushes and get about two gallon sized containers full each year per bush. I heat them slightly in a pan, mash them, and run them through a food mill that you can get on Amazon for about $40 USD. The food mill has several strainer sizes, so I do a 2 step process, the first is with the largest strainer then a second time with the medium one.
As for recipes, I normally make preserves with them. Here's my recipe:
2 cups goumi pulp
1 cup sugar
1.5 tbsp pectin
1 TSP lemon juice
Heat until it come to a boil for about 5 minutes, then pour into Mason jars.