Is simple:
1) Make a control sector.
2) Set one linedef to the trigger (Continuous, Once, Once Per Touch)
3) Set one linedef to be the fucntion (move floor, move ceiling, teleport)
4) Tag what you want the trigger sector to be to the linedef in step 2, set the trigger sector's (not control) sector type to be Linedef Executor (Floor Touch or No Floor Touch).
5) Tag the sector you want to be affected to the linedef in step 3.
Done'd