This is all there is to it unless you would like to make a washable pillowcase for the rice bag. The heat the rice bag gives off is gentle and moist and lasts an hour or more.
Some folks swear by rice, some use millet or flax from the health food store.
I've used them all and have no particular preference. They each have their own distinctive fragrance and seem to retain heat about the same. These bags can also be made long and skinny to sooth your tired computer neck.