Working hours fixed by such enchanting folk, on paper (4,8)

'working hours fixed by such' is the definition.
(switches that turn on automatically)

'enchanting folk on paper' is the wordplay.
'enchanting folk' becomes 'witches' (witches might enchant things).
'on' is a charade indicator (letters next to each other).
'paper' becomes 'times' (The Times newspaper).
'witches' put after 'times' is 'TIME SWITCHES'.