Setting up, help out guides initially (8)
I believe the answer is:
pitching
'setting up' is the definition.
('pitch' can be a synonym of 'set up')
'help out guides initially' is the wordplay.
'help out' becomes 'pitch in' (to pitch in is to provide assistance).
'initially' says to take the initial letters.
The initial letter of 'guides' is 'g'.
'pitchin'+'g'='PITCHING'
(Other definitions for pitching that I've seen before include "setting up" , "Putting up (a tent)" .)