Soldiers in street establish order (4)
I believe the answer is:
sort
'order' is the definition.
(I've seen this before)
'soldiers in street' is the wordplay.
'soldiers' becomes 'or' (Other Rank).
'in' is an insertion indicator.
'street' becomes 'st'.
'or' placed into 'st' is 'SORT'.
'establish' is the link.
This may not be right. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for sort that I've seen before include "Work out" , "Type, category" , "Arrange systematically" , "Tidy" , "Type - arrange in groups" .)