'N' key for the recognition manual if you haven't overwritten commands_en.cfg with another mod.
Magui replaces the stadimeter with a RaAOBF instead to determine range among other things (needs to be used as max zoom level)
Basic guide can be found here:
https://www.subsim.com/radioroom/sho...d.php?t=236013
But there are plenty of other guides (I got a pdf from somewhere on the forums years ago) that goes into detail