Before you start a tennis tournament, you will first need to register.

Go here to register.

Once you have registered, go here to create a tournament: https://www.globaltennisnetwork.com/tennis-tournaments/start-a-tennis-tournament

Running a tennis tournament is free. But, you may want to get a premium membership to unlock certain features.

You actually do not need to add the "Byes" to a tournament. Just place your players on the bracket, and when you are ready, you can "finalize the bracket". The system will then add "Byes" to all the empty spots.