this is a handheld gaming console.
you can play on it physical game cartriges you buy from a physical store
or play digital copies of game you download.
to download a digital game, you need to have an account at nintendo.com
then you can buy the game form the nintendo eshop site for you country.
once you bought the game, you get a code into your phones SMS and
your email. this code you enter in the console at the eshop menu,
next the game starts to download, (assuming you the device is connected to your internet network and isn't on airplane mode).
you can add additional memory with a physical SD card inserted into the switch device.
add a screen protector, or even a metal latch for the joycons.
the device can also connect to your TV using a docking station included a power cable and
the included hdmi cable.