Possible solutions of your questions

Hello

upload the website files to the public_html folder

create the database panel on the database menu and execute the database dump in phpmyadmin

create a database user, add it to the database and change the settings, podkluchenie in the configuration file.

In your current plan envisaged the use of 1 DB. For additional BD  you need to raise the tariff plan.

the Current database you can delete spanel in section MySQL Database.