How this would work (assuming this is map01)
SECTOR 1
(sector button is in)
floor=1000
ceiling=3000
tag=0
anything X anything
square
SECTOR 2
(button)
floor=1050
ceiling=3000
tag=1
effect=975 (trigger linedef, floor touch)
square
SECTOR 3 (control)
(run script linedef)
triangle
floor=001
ceiling=anything
LINEDEF 1
sector 3
type=98 (trigger once)
tag=1
LINEDEF 2
sector 3
type=113
tag=0
SECTOR 4 (control)
triangle
floor=1000
ceiling=3000
LINEDEF 3 (sector 4)
type=98 (trigger once)
tag=1
LINEDEF 4 (sector 4)
type=106
tag=1
note: length of line controls how fast the button descends.
Once you've got those sectors made, create a new lump with XWE or SLumpED, and name it SCR01001. Put the script in there to be run. Somethng like this
cecho "hi"
then, it should work.