Decoration put in bunk bed, essentially (7)
I believe the answer is:
rosette
'decoration' is the definition.
(I know that rosette is a type of adornment)
'put in bunk bed essentially' is the wordplay.
'put' becomes 'set' (both can mean to place or position).
'in' means one lot of letters goes inside another.
'bunk bed essentially' becomes 'rote' (I can't justify this - if you can you should give a lot more credence to this answer).
'set' placed within 'rote' is 'ROSETTE'.
Can you help me to learn more?
(Other definitions for rosette that I've seen before include "shape for diamonds" , "Ribbony badge" , "collection of ribbons" , "Ribbon decoration" , "Cockade" .)