After you have ordered a physical card, it will be mailed to you in a few business days. The time varies based on your location, but it generally takes around 5-7 business days to get to you.
Once you received the card in the mail, follow the directions in the mailer to activate your card. You will be asked to log into the app on your mobile device or web browser and select the unactivated card.
Then you will be asked to provide the last 4 digits of the card number and the expiration date to activate it.