Need Power???

Ever wonder how does pilot control the speed of an aircraft,well as shown in the picture that is the control stand.As you guys may already know that the 737-400 have 2 engines,if you seat at the pilot's seat you will have your number 1 engine on the left and number 2 on your right,that is what the numbers in the picture means if you push forward on the number 1 thrust lever it will only power the left engine and you will be flying side ways,we surely don't want that.

Maybe some will wonder what is the red light,well the red light is an indication of your parking brake as in handbrake in your car,when the light is illuminated that means that the parking brake is on or set