I'm not really sure but I know you put the ingredients in and the ice and salt goes around it. Then it makes it cold and creamy. You don't make the cream, you buy it at your grocery store. Look for...
Yes. Either whip it in a mixer or use a wire whip. Using an electric mixer is the easiest way to do it. But be careful not to overwhip or you will end up with butter and whey.
Pure cream high in milk fat is best for ice cream. Read the label: it should say, contains cream (and give the percentage of fat) and might also list the small amount of water which naturally occurs...