You plant potatoes in the spring. They can be planted in furrows. You can buy seed potatoes in catalogs or at nurseries in the spring. Cut up the seed potatoes so that each piece has an "eye". Plant the pieces several inches deep and at least six inches apart. When the leaves start to show add several more inches of soil. Keep doing that until you have a mound instead of a furrow. Each piece of seed potato will generate numerous new potatoes. Water as you would for other crops-regularlyso that the soil six inches down gets damp. That should be about every three or four days. More often can cause rot. When the vines at the top of the mounds go brown and die hand dig the potatoes out of the furrows.
It doesn't get much easier.
Cabbage can be planted from seed. Here in California it is a winter vegetable and can be planted right now if you hurry. You can also put in a crop in the spring after the last chance of frost.