Having created a new read replica, you will now need to create a MySQL user on it. Log into the read replica from a mysql client (e.g., MySQL Workbench) with the master account. Then create a user to be used only by FlyData Sync. You can do this in MySQL like so:
mysql> CREATE USER 'sync'@'%' IDENTIFIED BY 'your_password'; mysql> GRANT REPLICATION SLAVE, SELECT, RELOAD, REPLICATION CLIENT, LOCK TABLES, EXECUTE ON *.* TO 'sync'@'%'; mysql> FLUSH PRIVILEGES;
For your_password, enter the password you want to use for this new user.