You can install FCPX through the App Store, but if you're applying your educational discount, keep in mind that you might want to buy it first through Apple's Education portal, before opening the App Store and downloading it.
If you're looking to test this out before deciding to buy it, they do have a 90 day free trial available.
To start yourself off, you're going to need a Library to work in. These are essentially the file FCPX builds to manage your media.
Next up, you'll be given two Events, today's date, and "Smart Collections". Events are just FCPX's system of folders. A good practice is to start off creating two of them: "Footage" and "Projects". You can just rename the date, or go to
Events(Opt + N)
Now, you'll be given a nice "Import Media" button to start you off, but you can also
Media(Cmd + I)
This will open up a File Browser, just navigate to your footage, select it and hit Import Selected
Next up, you'll need a timeline to arrange all this footage into, in your Project event
Project(Cmd + N)
From here, you can normalize your project settings to what you shot your footage in. I recommend paying close attention to Resolution and Rate, most others will be selected automatically -- you can always change this later, if needed.
Finally, you're ready to edit, simply grab some of your footage and drag it down onto your timeline!