Grease the lower 1/3 of the Instant Pot insert with butter or coconut oil. Add water, salt then oats (and any other add ins you want).
Place lid on and lock. Turn on MANUAL mode with high pressure selected for 8 minutes, 10 if you prefer softer oats. Turn switch to VENTING and allow for the pressure to release manually, this usually takes 7-10 minutes or so. Remove the lid and stir.
Allow to cool until most of the liquid is absorbed. Stir in additional butter or a splash of milk, if desired.