How to make a shotgun boost effect?

I am currently working on a game, and I have guns already added and everything. There is just one component I want to add, but don’t know how. I want to make the shotgun so you can point in any direction, and when you jump(which I have this part covered), you get blasted in the opposite direction that you shot. I looked on YouTube for 2 days now and have no luck. If someone could help me out that would be great. Thanks! - Vance

This is what I have

if (readyToShoot && shooting && !reloading && bulletsLeft > 0)
            bulletsShot = bulletsPerTap;

            if (boostable && isGrounded == false) 
                player.GetComponent<Rigidbody>().AddForce(, ForceMode.Impulse);

I don’t know what to add in the AddForce() function to make me go in the opposite way I am looking

If anyone has answers for me, please make sure to @ me! Thanks

just multiply the direction you’re looking at with -1, then multiply that with your desired force amount