How to make the player UpperTorso face a part?

I want to Weld the upperTorso to face a part. I am making a gun using GUI. I'm not good at using tools that's why I am using GUI. The gun is weld onto the player's arm. The gun has a gui it can fire. While the player is firing the HumanoidRootPart is facing the target. All I need Is the UpperTorso to face the target so they can shoot from the roof on a player that's on the ground.

char.UpperTorso.Waist.C1 = char.UpperTorso.Waist.C1*CFrame.fromAxisAngle((script.Parent.track.targeting.Value).HumanoidRootPart.Position, 0)