I must admit that I don't know what 'cms' is, but anyway
If 'cms' is a event that you want to happen before Num3, its:
MapKey(WhatEverDevice,WhatEverKey,CHAIN(DOWN+cms,D(4000),UP+cms,PULSE+KP3)))
if 'cms' is a button that you want to hold for 4 seconds before something happens, its:
MapKey(cms-device,cms-button,TEMPO(0,PULSE+KP3,4000))
'KP3' is KeyPad-3
'4000' is 4000 miliseconds