Starts off on board to attend to watch (7)
I believe the answer is:
observe
'watch' is the definition.
(observing is a kind of watching)
'starts off on board to attend' is the wordplay.
'starts off' says to take the initial letters.
'to attend' becomes 'serve' ('serve' can be a synonym of 'attend'**).
The initial letters of 'on board' is 'ob'.
'ob'+'serve'='OBSERVE'
'to' acts as a link.
(Other definitions for observe that I've seen before include "Spot, watch" , "Watch without intervening" , "Notice or conform to, rules say" , "Notice; study" , "Watch, take note of" .)