These M4T Knowledge Base articles may answer your question.
Using the K-14 gunsight: http://www.mission4today.com/index.php?name=Knowledge_Base&op=show&kid=369
Use the 'Toggle Sight Mode (Auto)' button to switch gunsight mode. Use the 'Adjust Sight Control to Right' and 'Adjust Sight Control to Left' buttons to select the target aircraft type. Use the 'Increase Sight Distance' and 'Decrease Sight Distance' buttons to adjust the sight circle for the target aircraft to fit in it. Track the target aircraft for at least 2 seconds to maintain correct lead.
Using the Stuvi gunsight: http://www.mission4today.com/index.php?name=Knowledge_Base&op=show&kid=370
Before the dive in your Ju-87D-5 (Ju-88.) you must set your dive airspeed (true) by buttons 'Increase Sight Velocity' and 'Decrease Sight Velocity' and bomb drop altitude by buttons 'Increase Sight Altitude' and 'Decrease Sight Altitude'.
When the plane enters the dive you must place the crosshairs onto your target and keep it there. When the plane reaches the preset altitude the warning horn will sound.
The pilot should drop the bombs at this point, after which point the plane will be automatically leveled off.
The Gunnery section may have more information that is of interest to you.
Gunnery section at M4T: http://www.mission4today.com/index.php?name=Knowledge_Base&cat=44