The game comes directly from Nintendo eShop, you will be able to go online, get updates etc.
After setup process the game will be available to launch on your own account, just as any other game or app you purchased directly in Nintendo eShop.
Step into the shoes of Shez as they join Edelgard, Dimitri, Claude, and other Fire Emblem™: Three Houses characters and fight for the future of Fódlan. Align with a leader to build and command an army in strategic 1-vs.-1,000-style battles. The house you choose will bring you through one of three compelling stories, each with a different outcome.