Open your NookPhone
Select Best Friends List
Use the Nintendo Switch Friend List to add friends first
Visit Orville at the airport
Choose I want visitors
Select Via online play or Via local play
Choose Invite via Dodo Code or All my friends
Share your Dodo Code with the friend you want to invite
Have your friend visit your island using the code
Open your gate if you want friends to come over
Add players as Best Friends after they visit
Accept friend requests on Nintendo Switch if needed