Working with APIs for the first time

I'm fairly new to programming and recently I came across APIs. I am trying to use an API which, I think, will save the data in an XML file which I can import into a Microsoft excel spreadsheet. The API I am trying to use is called marketstat and the data given for it is on this link http://ift.tt/1tPWKsZ

Unfortunately I am unaware of how to use an API and I was hoping someone will give me an example of how to use this API correctly so that I may use it

Thanks,