Do you see the "blue clouds" icon in your system tray (near the clock might need to click the arrow to show more). On the SP3, One Drive Business is a desktop app that syncs files from your library to a drive on your computer. The easiest way to add the sync is to browse to your OneDrive in IE and then click the Sync icon. It should interact with the desktop app from what I remember to walk you through the process. It has been a little while, but I think that was how it worked...
It is vastly inferior to their consumer OneDrive sync engine. Lots of issues syncing when I've used it over the last couple months. Not just on the SP3 but on my other laptops as well. Gotta love the amount of space they give you though!