Move to a higher position by mistake! (4-2)
I believe the answer is:
slip-up
'mistake' is the definition.
(I know that slip-up is a type of mistake)
'move to a higher position' is the wordplay.
I cannot really see how this works, but
'move' could be 'slip' (slip is a kind of move) and 'slip' is located in the answer.
'higher' could be 'up' and 'up' is found in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
'by' acts as a link.
Can you help me to learn more?
(Other definitions for slip-up that I've seen before include "Small error" , "Minor lapse" , "Mistake, blunder" , "Minor inadvertent mistake" .)