To turn URL into a GET Command it must turn from this format (This only an example, it wont do anything):
to this format:
Simply take whatever comes after the main website address (or in some cases IP address) and put them between the word GET and the HTTP part of the GET request.GET /getvariables/home.html HTTP/1.0\x0D\x0A
Note - some devices require a HTTP 1.1 specification command, which has extra parameters (Host etc) - please refer to general HTTP documentation for more information.
From here you can assign the commands to buttons as normal apart from the fact that when creating a device you must enter the website (or IP Address) as the address for the device.