It is not advisable or best practice to use the 'super user root' for your database, create a new user and leave user root for System use only or you could create a security risk.
Click on Privileges and select Add a new user.
When you have added your user click on Generate - do not add privileges yet.
Once you have done that then go back to the Home page and select privileges again and find the user you created and select the edit icon on the end of the line,
This is where you add privileges for that user for the database you created only.
This old post by my dear friend Izzy did a tutorial type post for creating a Wordpress database and although phpMyAdmin has changed slightly the general gist of the information is the same and may help especially if you copy and paste the content to a text file for future use. viewtopic.php?p=112258#p112258
We will have you all sorted soon.