Once installed, log into the application using the same Ubisoft account used for your purchase.
Your game will be located within the Uplay PC applications GAMES list as soon as your purchase is complete, where you can download, install and launch your product.
For DLC/ULC (additional content) purchases, content will normally be available in-game automatically. Simply launch the main game to access your content.
Please note that DLC purchased on the Uplay Shop will work with all versions of the base game with the exception of those purchased on Steam.