Wash outsides of vegetables. Then on a cutting board slice both into 1" pieces or so. The smaller they are the softer they will get.
Pour 1.5 cup of water into pressure cooker inner pot and lower a vegetable steamer into the bottom.
Put cubed vegetables inside the basket, sprinkle with salt and pepper. You could add a few slices of butter on top as well so that melts as it steams.
Close lid and steam valve. Set to high pressure for 3 minutes and then do a quick release. Serve!
Alternatively if you like your veggies REALLY tender you can omit the steamer basket and put directly into pot with 2 cups water or broth. Salt the water on top and cook on high pressure for 3 minutes. Drain, season and serve.