Start to go and file in comprehension (5)
I believe the answer is:
grasp
'comprehension' is the definition.
(I've seen this before)
'start to go and file' is the wordplay.
'start to' indicates taking the first letters.
'and' is a charade indicator (letters next to each other).
'file' becomes 'rasp' (rasp is a kind of file).
The first letter of 'go' is 'g'.
'g'+'rasp'='GRASP'
'in' is the link.
(Other definitions for grasp that I've seen before include "Get hold of firmly" , "Seize - comprehend" , "Catch on" , "Hold - understanding" , "Lay hold of" .)