Add the bones, salt, vinegar and any additional ingredients to the insert of your Instant Pot. It's okay if the bones stick up past the top of the insert as long as you can get the lid on. If you can't get the lid on, break the bones so they settle lower into the insert.
Add filtered water. If the bones stick up past the top of the insert, don't fill the water to the maximum capacity line on the inside of the insert so as to leave room for the bones to settle down into the water. If the bones don't stick up that far, then add water until it reaches the maximum capacity line. You'll need about 8-10 cups of water total.
Lock on the lid and make sure the release button is in the seal position.
Press the Manual button and press the + button until the screen reads 90 minutes if the bones are frozen, 60 if they're room temperature. (Note: different electric pressure cooker models might have different buttons - follow the instructions for your specific model to cook the broth for 60 or 90 minutes.)
Once the 60 or 90 minutes are done, press the Keep Warm/Cancel button to turn the IP off. Let the broth rest for at least 20 minutes.
Line a colander with cheesecloth and set it over a large mixing bowl. Keep a plastic bag nearby for the discarded bones (make sure the bag doesn't have any holes).
Release the pressure and unlock the lid. Carefully pour the hot broth into the lined colander. Then lift the colander up to drain completely into the bowl.
Add the bones, veggies and cheesecloth from the colander to your plastic bag, seal/tie it up and discard.
Pour the broth into a refrigerator-safe container and chill for 24-48 hours. The longer you chill it, the more the fat that rises to the top will solidify and be easier to remove.
After 24-48 hours, remove the fat that's solidified at the top of the broth and portion out your broth into your preferred container for freezing or chilling.