My bf wants me to cook a roast in a pressure cooker. He claims it will be the most tender roast I have ever had, but I've never used a pressure cooker, and he doesn't know much about it either, because he is just going by what his grandma used to do. He claims it only takes about an hour. I assume the liquid should be about halfway up the roast? And should I put the vegetables on top, or under the roast, or wait til the end to put them in? What temp should it be on? Any tips and recipes would be appreciated thanks in advance!