Assemble to do some harvesting (6)
I believe the answer is:
gather
'assemble' is the definition.
(synonyms)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for gather that I've seen before include "Congregate" , "Assemble - conclude - contract" , "Assemble; understand" , "Accumulate, amass" , "Bring or assemble together" .)