Like in real world, you use Elevator to go to the destination within the building or within the area which gives convenience to the people instead of taking stairs. In World Elevators allow you to go to Turfs or Shops that is in the same area as long as it's open for public. You cannot use the Elevator to go to Turfs or Shops that is not within the location otherwise use Teleporter.
To use Elevator, click the Elevator then select the shop or turf where you want to go. If it's not in the list click "other" and type the name of the turf or shop.
You can pause and play as you follow the video guide