I made this tutorial after a request in the forums was made for it. It will show you how to teleport from one location to another.
Start off with the room your player will teleport from. Create a brush textured with nodraw and place it where the player has to walk to be teleported. As soon as a player touches any sides of this brush they will be teleported. That is after the entity work of course. As you can see I have a very basic setup.
Select the brush and press ctrl+t then choose trigger_teleport from the list. The only setting needed to be changed is Remote Destination which you give a name. I have chosen tele and will be reffering to this name throughout the tutorial.
Next have your teleport location. Select your entity tool and place it where you want players to be teleported to. While the entity is selected press alt+enter to bring up the properties box. From the list choose info_teleport_destination and Name it tele. It will look something similar to this.
Thats it! Compile and test.