Before placing the ribs into the oven you should preheat the oven to 400 degrees and while the oven is preheating you should season the entire ribs with salt and pepper.
After doing that then you can place the ribs into the oven and then let the ribs cook for 1 hour and 30 minutes or until the ribs become tender where you can easily pierce the ribs with a fork.
This is also knows as fork tender.
The ribs should be fully cooked and ready to eat after 1 hour and 30 minutes in the 400 F oven however if not cooked enough to your desires you can cook them a little longer.