This is so easy. If your compound butter has salt in it, then you probably don't need to salt your steak in addition to the butter. That's personal preference though.
Place 1 Tablespoon of compound butter on each steak and spread it around, covering as much surface area as you can.
Place each steak into a vacuum seal pouch and use your Food Saver (or other brand) to remove the air and seal the pouch. At this point, your steaks can be frozen for future use, or you can go ahead and begin your sous vide process.
Place your pouches into your prepared pot. Follow the instructions in your manual, filling the pot with water to the appropriate level. Try using warm water so that your pot will get up to temp more quickly, otherwise the Instant Pot can take a very long time just to get up to temp.
If you are looking to cook a perfectly rare steak and finish it on the grill or under the broiler, then your steak needs to come out of sous vide a bit underdone. This way, your steak won't overcook when you do the final sear or browning. I set my pot to 118° for 2 hours. This works for us. We like our steaks rare so I go for 5°-7° below where I want them to be. (chart is from certifiedangusbeef.com)
When steaks are done, you can place them under the broiler until they are nicely browned.
Flip and do the other side as well.
It's perfect every single time.