Add a teaspoon of salt to each clean, prepared jar.
Cut up the potatoes. Any size, as long as they are smaller than 2 inches in diameter. Just keep in mind what you'd like to use them for
Boil the cut potatoes in boiling water for 2 minutes.
Pack the diced potatoes in the jars tightly.
Add water to the jars. Leave about 3/4 inch headspace at the top of each jar. Make sure that the potatoes are packed tight and covered by the water.
Use a small spatula or some kind of tool around the outside of the inside of the jar to remove any air bubbles. Add more water if necessary.
Clean off the tops of the jars. Place lids on top of the jars and screw the rims on tightly.
Place the jars in the pressure canner. Add exactly 3 quarts of water (if you are using a Presto 23 Quart Canner as I do, otherwise follow the directions for pressure canning for your specific canner). Do not put the lid on. Turn the burner on high and watch until the water reaches the boiling point or just before. Then put on the lid and make sure it is properly sealed in place. (Please see your canner's manual for specifics on how your canner is sealed properly.)
Let the canner begin building pressure for about 5 minutes before you put the weight on. When you see steam come out of this area, then put the weight on. Now the pressure will start to build.
Once your pressure comes to the pressure, process according to the recommended time. You will have to stay in the kitchen with it to make sure it stays at the required pressure. You may have to turn the burner between low and high (or maybe even off occasionally to be able to keep it at the correct pressure.
Once you've processed your jars at the recommended pressure for the recommended time, turn off the burner and leave the canner to sit. Do not touch or open the canner until the air vent/cover lock goes down and the pressure gauge goes all the way back down.
After removing the jars from the canner, make sure all jars have properly sealed.