One of the highlighted features of Airdroid is it works using WiFi to connect a computer to your mobile device, NO cables ever required. While you can set up an online Airdroid account I prefer to just ignore that feature and just transfer files back and forth to my computers using my home WiFi. All you need is the Airdroid app on your Nexus, no need to add anything extra on your computer as you'll only be using its web browser (and so far I've had no problems using Firefox, Chrome, Chromium, Opera, IE, and Safari on a mix of Linux, Windows, and OS X boxes). Just launch the Airdroid app, a window will pop up with http:// web.airdroid.com highlighted but also in much smaller type below an IP address/port number, in my case it's something like
http://10.0.0.5:8888. Ignore the highlighted one, that's what you'd use if you set up an online account. Just type that IP/port into whatever browser you use on your computer, a confirmation button will pop up on your Nexus, and that's about all you need to do. Your browser will fill with a page that's accessing your Nexus. As you'll see Airdroid allows you to do a lot more than just transfer files back and forth. (i.e. control your Nexus' camera remotely from your computer)
Oh, and don't forget that Google, for whatever nutty reasons, as of KitKat has restricted user access to only certain directories on external SDcards, at least for third-party apps. So unless you've rooted your Nexus, you need to use something like Android's 'My Files' app to move files/folders around.
