A set of steps doesn't start burning (6)
I believe the answer is:
alight
'burning' is the definition.
(set alight)
'a set of steps doesn't start' is the wordplay.
'set of steps' becomes 'flight'.
'doesn't start' means to remove the first letter.
'flight' with its initial letter taken off is 'light'.
'a'+'light'='ALIGHT'
(Other definitions for alight that I've seen before include "Burning; get down" , "Disembark, land" , "(Of bird) settle" , "Descend, from a bus or train say" , "Ignited; get off" .)