Prepare for business session about returning deposit before operation (3,2,4)
I believe the answer is:
set up shop
'session about returning deposit before operation' is the definition.
I know nothing about this answer so I can't tell whether this works.
'prepare for business' is the wordplay.
I cannot quite understand how this works, but
'prepare' could be 'setup' (setting up is a kind of preparing) and 'setup' is present in the answer.
'business' could be 'shop' (I've seen this in another clue) and 'shop' is found within the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for set up shop that I've seen before include "get business going" , "get market going" , "start operations" , "Begin trading" , "begin operations" .)