Sending web requests with IFTT and the Maker Channel

So I am attempting to send a web request via the maker channel on If This then That to a Arduino (and Ethernet shield) to turn on a led. From what I understand, I would send a POST request to the boards url and it would set the led state to high. However I am fairly new to this kind of stuff and I really do not know where to go from there. What sort of text would I put in the Maker Channel body? I do know that its JSON. Also more importantly how would I configure the Arduino and web server to receive the POST request?