For a pressure cooker pot roast--
I brown the roast (3-3.5 lbs boneless chuck) in a little canola oil in the pressure cooker on both sides. I add 1-3 whole peled potatoes, a handful of the mini carrots, some peeled garlic cloves, and either two small (larger than ping-pong balls, smaller than tennis balls) peeled onions, or if I am supremely lazy, a packet of onion soup mix.(Remember, no more than 2/3 full of solids!)
If you don't want to brown it, or are really pressed for time, spread both sides with soy sauce. Gives a nice appearance.
I then add 1 1/2 cups lower salt chicken broth {or however much your cooker needs}, (canned beef broth is nasty), and then lock it, and bring it up to pressure.
35 minutes later, turn off the heat, remove it to a cool, yet heat resistant place (unused burner/element is ideal) and let the pressure drop naturally.
If you quick release, chances are it will be unacceptably tough.
Take the meat and vegetables out, and if you want gravy, you can make it there in the cooker. Loosely cover the roast and vegetables with aluminum foil when you do. Let the roast rest 10-20 minutes before carving.
There you go!
Lawrence/Maytagbear