I am not sure where you can find information on the operation of the instrument.
All of the settings are controlled by a small keypad that you plug into the instrument. There is a list of codes, which you use to view the information you need. For example you input one code to see what the high voltage is, another for battery. The instrument can easily be configured for a variety of detector and you can switch between them using another set of codes. The data is then downloaded into a computer after you survey. They work pretty well but require more computer type skills and after several days you probably will remember the codes but keep the Command manual close. Just realize that basically there is one switch on the instrument and it is the power switch everything else is controlled by the key pad.
I hope this helps a little. Good luck