Finish program referred to earlier and attach it (6)
I believe the answer is:
append
'referred to earlier and attach it' is the definition.
I can't judge whether this defines the answer.
'finish program' is the wordplay.
I cannot really understand how this works, but
'finish' could be 'end' (come to an end) and 'end' is located in the answer.
'program' could be 'app' (type of computer program) and 'app' is found in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for append that I've seen before include "Add (to end of text)" , "Add (at the back of a document)" , "Add on, attach" , "Affix to the end" , "Hang on" .)