This is a really basic question. I'm a college sophomore and I have no experience downloading APIs to use with Java, but I'm working on a personal project in which I need to be able to read in Microsoft Excel files. I'm trying to download Apache POI, which I saw recommended here. I might just be dumb, but I can't figure out where I should be downloading it to or how to verify the integrity of the files, which the download page says it "essential". 

The download page is here: <http://poi.apache.org/download.html#POI-3.17>. If someone could just give me an idea of how to do this, that would be great, because I'm sure it's a skill that will help me in the future.