Newly alerted one may have to step on it (7)
I believe the answer is:
treadle
'to step on it' is the definition.
(I've seen this in another clue)
'newly alerted' is the wordplay.
'newly' is an anagram indicator.
'alerted' with letters rearranged gives 'TREADLE'.
'one may have' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for treadle that I've seen before include "Foot lever powering machine" , "Alerted (anag)" , "Pedal operating machine" , "Foot-operated lever" , "Rocker in a factory" .)