Make sense of reporting to base (10)
I believe the answer is:
Here is my best explanation:
'make sense of' is the definition.
(I've seen this before)
'reporting to base' is the subsidiary indication.
'reporting to' becomes 'under'.
'base' becomes 'stand' ('stand' can be a synonym of 'base').
(Other definitions for understand that I've seen before include "Dig", "Grasp - sympathise", "Perceive the meaning of", "See", "Make sense of", "see", "Get the message", "Comprehend" and "Twig".)