How to use a stair climbing machine and look smart (4,2,2)
I believe the answer is:
step on it
'climbing machine and look smart' is the definition.
I know nothing about this answer so I cannot judge whether this works.
'how to use a stair' is the wordplay.
I cannot really understand how this works, but
'stair' could be 'step' (synonyms) and 'step' is located in the answer.
The remaining letters 'onit' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for step on it that I've seen before include "Hurry! - set point (anag)" , "Go for speed" , "Informally, hurry or drive faster" , "Hurry up, put foot down on pedal" , "be quicker" .)