C# | How do I move an object a number of units?

Under what void do I use this on? When I used void Update, it didn't move by how much I wanted, it moved by more than that, and that's not what I want. In my script, I need the gun to move 1.2 units to the left, even if I am holding the right mouse button. Here's my script for a gun aiming:

     public bool isAiming = false;
 
         if(isAiming = false && Input.Get$$anonymous$$ey($$anonymous$$eyCode.$$anonymous$$ouse1)){
             transform.Translate (Vector3.left * 1.24822076f);
             isAiming = true;
         }
         if(isAiming = true && Input.Get$$anonymous$$ey($$anonymous$$eyCode.$$anonymous$$ouse1)){
                 transform.Translate (Vector3.right * 1.24822076f);
                 isAiming = false;
             }
                 
 
     
     }
 }