Put down some things to sit on, perhaps (3)
I believe the answer is:
lay
'put' is the definition.
('lay' can be a synonym of 'put')
'down some things to sit on perhaps' is the wordplay.
'down some things' becomes 'la' (I can't justify this - if you can you should give a lot more credence to this answer).
'to sit on' says to put letters next to each other (in a down clue, some letters go on top of others).
'perhaps' becomes 'y' (I've seen this in other clues).
'la'+'y'='LAY'
Can you help me to learn more?
(Other definitions for lay that I've seen before include "Narrative poem" , "Was lying" , "Air" , "Put down; lyric" , "in which hens regularly produce eggs?" .)