Find large Mexican pancake flipping excellent at first (6)
I believe the answer is:
Here is my best explanation:
'find' is the definition.
(locating is a kind of finding)
'large mexican pancake flipping excellent at first' is the subsidiary indication.
'large' becomes 'l'.
'mexican pancake' becomes 'taco' (I've seen this before).
'flipping' shows that the letters should be reversed in order.
'at first' says to take the initial letters.
The initial letter of 'excellent' is 'e'.
'taco' back-to-front is 'ocat'.
(Other definitions for locate that I've seen before include "Find out where something is", "Set in a particular place", "Discover the place where something is", "Track down", "Pinpoint the position", "Discover the exact position of", "Find or situate", "Establish", "Find by searching" and "Discover place where thing is".)