What version of Ubuntu?
How are you trying to import it?
From a file located in the “File Manager”
Where is the database coming from?
I uploaded it there, it’s from a website theme file
What are you importing the database to?
To a database associated with the subdomain where the theme files are uploaded.
What exactly are you doing?
I need to install a website.
You don’t use file manager to manage databases. You use either the database manager dialogue or phpmyadmin.
Example: If you’ve created a new virtual server and you’re moving a Wordpress site to that virtual server, you would back up the database from the old server, install Wordpress on the new server, move your old Wordpress site to the new site and then use phpmyadmin to merge the old database into the new database.