Note however that the virtual switch is only one part of a multistep process.
One) first you must purchase a networked device which is capable of controlling your garage door.
The only one which is on the official “works smartthings list” is the gocontrol from Linear. (This is the same as the linear GD 00z series) .
http://www.smartthings.com/compatible-products/
Other popular models include the Chamberlain myQ and the Telguard.
Two) once you have the networked garage controller installed and running, you add it to the smartthings network. The exact method will vary slightly depending on the brand you picked.
Three) now you create the virtual switch. Using instructions in my previous post.
Four) now you must associate the garage control device with the virtual switch. The exact method will vary slightly depending on the garage door device that you chose. Community members will be able to help you.
Five) once the two switches are associated, then turning on the virtual switch will open the garage door and turning off the virtual switch will close it. So now we just want to be able to turn on and off the virtual switch by voice.
So now you just have to authorize echo to request smart things to turn the virtual switch on and off. See the following FAQ.