Harvest about a thousand and make a new chart (5)
I believe the answer is:
remap
'make a new chart' is the definition.
I don't know anything about this answer so I cannot judge whether this works.
'harvest about a thousand' is the wordplay.
'harvest' becomes 'reap' (synonyms).
'about' is an insertion indicator.
'a thousand' becomes 'm' (Roman numeral for a thousand).
'reap' going around 'm' is 'REMAP'.
'and' is the link.
Can you help me to learn more?
(Other definitions for remap that I've seen before include "Survey (area) again" , "(In computing) change the assignment of a function to a key" , "Make new plans" , "chart again" , "Draw a plan again" .)