Instruct every team leader to go first (5)
I believe the answer is:
teach
'instruct' is the definition.
(I know that instruct can be written as teach)
'every team leader to go first' is the wordplay.
'every' becomes 'each' (synonyms).
'leader' suggests taking the first letters.
'to go first' means one lot of letters go next to another.
The initial letter of 'team' is 't'.
'each' after 't' is 'TEACH'.
(Other definitions for teach that I've seen before include "Pass on knowledge" , "Coach" , "Impart knowledge" , "Tutor" , "Provide learning to" .)