He advises people to go to high ground (6)
I believe the answer is:
mentor
'he advises' is the definition.
(I've seen this before)
'people to go to high ground' is the wordplay.
'people' becomes 'men' (men are people).
'to go to' says to put letters next to each other.
'high ground' becomes 'tor'.
'men'+'tor'='MENTOR'
(Other definitions for mentor that I've seen before include "Train" , "No term for instructor" , "One guiding" , ""Guide, philosopher, and friend"" , "One who steers" .)