To be the boss, you need dash! (3)
I believe the answer is:
run
This clue is a triple definition!
'to be' is the first definition.
(running is a kind of being)
'the boss' is the second definition.
(thesaurus)
'you need' is a link.
'dash' is the third definition.
(thesaurus)
(Other definitions for run that I've seen before include "Race; manage" , "Manage; flee" , "follow a course" , "freedom of access" , "Organise - series" .)