You need to activate your purchased Nintendo Switch key in the Nintendo eShop, which can be found in the console Menu:
- In the HOME Menu of the console, select "Nintendo eShop"
- Select the account where you want to activate the code
- On the left side of the screen, select "Redeem Code"
- Enter the 16-digit code you purchase and click "Confirm"
- The product will start downloading
The purchased Nintendo 3DS/2DS key needs to be activated in the Nintendo eShop, which can be found in the console Menu:
- In the HOME Menu of the console, select "Nintendo eShop"
- Select "Menu" and then "Redeem Download Code"
- Click the field with "Enter a download code" text
- Enter the code you purchased and click "OK"
- Click "OK" again and select "Download Now" if you want to start downloading immediately
