Fold and fit into the lower part (2,5)
I believe the answer is:
go under
'fold' is the definition.
(thesaurus)
'fit into the lower part' is the wordplay.
I cannot quite see how this works, but
'fit' could be 'go' (go can mean to fit or match) and 'go' is located in the answer.
'lower' could be 'under' (under means lower down) and 'under' is found in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
'and' is the link.
Can you help me to learn more?
(Other definitions for go under that I've seen before include "Sink" , "Become bankrupt" .)