Find the start to the event (5)
I believe the answer is:
trace
'find' is the definition.
(I know that trace is a more specific form of the action find)
'start to the event' is the wordplay.
'start to' says to take the initial letters.
'event' becomes 'race' (race is a kind of event).
The first letter of 'the' is 't'.
't'+'race'='TRACE'
'the' is the link.
(Other definitions for trace that I've seen before include "Side strap connecting a horse to what it's pulling" , "Seek out" , "a little bit" , "Discover whereabouts" , "Make a copy using semi-transparent paper" .)