Here's what I did:
I cut my seed potatoes in half and made sure each piece had a couple of eyes. Some are already sprouted. Let them sit for about a day so the cut side heals before you plant.
Put a couple inches of dirt in the bottom of your container. This is a rubbermaid tote, not sure how many gallons it holds, but you'll see a better pic farther down.
Place your potatoes in the container, cut side down on top of the dirt. Make sure your eyes/sprouts face up. Space them out so they aren't too crowded. You could put less than I have, but I plant like this in case some of them don't produce.
Pour dirt over the top of the seed potatoes. 2-3 inches is good. Then, when the plants appear and have several leaves/shoots, pour another 3-5 inches of dirt over them to encourage more tubers. You can continue to add dirt over the new leaves/shoots until you have about 2 inches left at the top of the container.
I planted Kennebuc White potatoes in the blue container and the two smaller containers have red potatoes. I plan to harvest them as small new potatoes. I planted them the same way but there are 4 pieces in each of the smaller containers. The patch of dirt in front of the containers is where I dumped out the potatoes from last year. I planted some potatoes in that dirt to see which produces more potatoes. I'll just hoe the dirt over the top of them as the plants grow. The dirt looks dry, but it was wet when we put it in the container and since we are expecting rain today I won't put any additional water on them until I see how much rain we get.
So, there you have it. You can dig up "new" potatoes when the plant flowers, or wait and harvest all your potatoes when the plants have died back and they are turning yellow. I'll post more pics when I harvest the red potatoes as new potatoes.
Oh, I took pics of my bunching onions that are still growing in the garden and my garlic. They are doing well. The bunching onions will get a seed head in the tops of the greens and then fall over and plant itself and produce more onions. I planted my garlic last spring, so it's had two growing seasons. It died back in the summer and started growing again in the fall and has been green all winter. I thought they would die back after the two foot snow we had....but they didn't. I have to do some research but I think I might be able to dig up some garlic in late spring. If not, I'll wait until fall. I'm excited! Oh, and pay no attention to the fact that my garden is not weeded and perfectly ready for planting. It will be soon. Right now I'm pulling the weeds that I let grow as a "cover crop" and feeding them to the chickens. They love them! I'm also considering allowing our chickens to scratch around and eat some of the grubs that may be hiding in my dirt. Just have to figure out how to pen them up.
Close up of garlic