Set up in booth (7)
I believe the answer is:
install
'set up' is the definition.
('install' can be a synonym of 'set up')
'in booth' is the wordplay.
'booth' becomes 'stall' ('stall' can be a synonym of 'booth').
'in'+'stall'='INSTALL'
(Other definitions for install that I've seen before include "Set in place" , "Put into position, ready for use" , "Emplace" , "Lodge" , "Put in - invest" .)