In the body of the pressure cooker is lentils with enough water to cover them. The first bowl in the stack has barley, and its cooking liquid. Atop that, I set the little trivet that came with the pressure cooker. Atop /that/ are some red potatoes, with a scant 2 cm of water in. There'll be plenty of steam in the cooker, so I need not even bother with it, but I don't want the potatoes sticking to my bowl. I then put the lid and weight on the whole mess, set it over high heat, and set my timer for 40 minutes. (Next time, I'll go with shorter time, because the potatoes got overcooked). Then I walked away, and heard the pressure cooker get to full pressure at like 6 minutes or so. Then, I dropped down the heat to low, and let the timer run out. I did a quick release. Honestly, if I just did like 20 minutes, I could have still done a quick release with no problems. I was just stupidly nervous. Boo.
My friend Christy Morgan, of Blissful Chef fame, is maintaining an ongoing pressure cooker party on her blog. Please check out this link for more info on cooking other stuff in pressure cookers! She's got lots of creative ideas for cooking in my style: whole ingredients, lots of produce, and minimising premade stuff. Check it out!