First, of course, you need an Apple ID. If you don't have one it's easy as pie to create. This feature, and a couple of others use the Apple ID to link your devices together.
Open System Preferences and click on the iCloud icon.
You will need to click the "Connect" button and authenticate with your home computer user credentials. It will take a moment or two for the window to refresh with all your folders and files, but you can click on what you want and copy it to your laptop. Needless to say, your computer at home should be left turned on for this to work.