Pressure cookers work best with what would otherwise be long-cooking foods: beans, roasts, etc. Foods cook at higher temps under pressure so cooking times (and fuel consumption) can be greatly reduced.
Unless otherwise specified, recipes use 10lbs of pressure.
dry beans
Dry beans can be covered with sufficient water and cooked for ~30 minutes at 10lbs. This results in a firm bean that can be reheated a few times without breaking down.
heat oil in bottom of pressure cooker
add chilis, onions, black pepper, etc, brown to taste
add rinsed dry beans
bring to 10lbs pressure and hold for 30mins.
Remove from heat and allow to cool.
potatoes
wash and cube potatoes
place in steamer/colander
add water for steam, about to bottom of steamer
process at 10lbs for ~7mins
remove from heat and allow to cool
sterile water
Water can be sterilized (for first aid, etc) by processing under 10lbs pressure for 10mins.