I made the Numpad my "Bomber Sight Controls" for easy to train others with.

N.P.5= Bomb Sight Lock Toggle
N.P.7= Increase Sight Distance
N.P.1= Decrease Sight Distance
N.P.4= Adjust Sight Left
N.P.6= Adjust Sight Right
N.P.8= Increase Sight Altitude
N.P.2= Decrease Sight Altitude
N.P.9= Increase Sight Velocity
N.P.3= Decrease Sight Velocity
You need to assign "Level Stabilizer" to a key or button on your stick.

Once you look at your Numpad it should make some sense. 7, 8, & 9 are to Increase.
1, 2, & 3 are to Decrease. 4 is left 6 is right and 5 is toggle Bomb Sight lock on and off.

First thing we need to know is how high we want to be. Second how high our target is above 
Sea Level. If we are going to fly at 4,000 meters and our target is 1,000 meters above sea
level we would set our Altitude to 3,000 meters. Third is how fast we will be traveling in 
True Air Speed. With the Speed Bar enabled, it tells the speed in true air speed.
If the speed bar is not enabled,and you are using your instrument gages, 
this is indicated air speed, true airspeed is faster.

Enroute to target I set my Level stabilizer on. Hit C to switch to Nose Gunner/Bombadier. 
In the Betty it is the first time, then hit Shift F1 to bring up the Bomb Sight.
Set my Altitude on the Bomb Sight using NP 8 to raise, if you go to far use NP2 to lower.
Set my true airspeed using NP 9 to raise if you go to far use NP 3 to lower. Now exit your 
Bomb Sight by hitting Shift F1. Hit C until in Pilot Seat and turn off Level Stabilzer. 
Fly to the Ingress point and jump to your Bombadier position. Line up on Target Area and
turn on your Level Stabilizer on. Hit Shift F1 to bring up the Bomb Sight.
Now use NP 7 to raise the Bomb Sight up to the target area. You will use NP 7 and NP1 to
position the Sight up or down to line up on your target.When you see your Target, lock 
the Bomb sight using NP 5. If you need to adjust your sight left or right I usually turn off
the Level Stabilzer and make small corrections then turn it back on.

Now if everything is set correctly the bombsight crosshairs will not move from the target.
Usually it does move and the culprit is most likely the true air speed. 
If you’ve set your TAS too low the crosshairs will move “up” away from the target, and
vice versa for too high set TAS. So the crosshairs are close to the target (and not moving)
its a waiting game now. The bombsight will automatically release the bombs, as soon as this 
happens you can set the bombsight angle to zero and watch.