First, brown your meat. Press sauté on your pot (use the More setting) and let your pot heat up and say HOT. Add 1 Tbsp of oil and swish in the pot and then add your meat. When meat is still pink and halfway browned, 2-4 min, add oregano, garlic, and sea salt. This process seasons your meat directly and adds another layer of flavor.
Cook your meat for about a minute or two, until about halfway cooked. (Drain any grease if necessary. If you use a lean type of meat, then you won't need to drain). You don't need to wait until the meat is fully cooked to start pressure cooking. The meat will finish cooking during pressure cooking.
Deglaze your pot with 2 cups of beef broth. Beef broth will give your pasta and sauce a rich flavor boost. This is another layer of flavor you are adding to your dish. Then add your water. Break spaghetti noodles in half and arrange noodles going every-which-way. Like pick-up sticks or Kerplunk. Your spaghetti noodles should be crazy everywhere in the pot. Don't stir.
Pour sauce right on top of your crazy noodle mess. Don't stir. Don't worry about your noodles being under the liquid. With spaghetti, every strand doesn't need to be submerged. The noodles will cook down fast on their own and fall into the liquid during the cooking process.
As for timing your pasta dish, cook spaghetti for 4 min and QR. (See notes about pasta timing)
When your pasta is done, open up the pot and stir very well. Place the lid back on the pot and let sit for an additional 3 minutes. During this time your sauce with thicken and your pasta will finish cooking through.