In case anyone else is confused, this was actually quite easy.
1) Download the script mentioned above from StencylForge.
2) Create a new actor with the image of the tile you want, i.e. so it looks the same.
3) From the 'Elevator Move Horizontal' script, click the 'Attach to Actor Type' and select your actor.
4) Ensure you update the appropriate left and right 'x' values.
5) Place onto your scene.