Host-error

As I try to log onto (site-name)/wp-admin/install.php and end the whole thing, I get this message:

This either means that the username and password information in your wp-config.php file is incorrect or we can’t contact the database server at localhost. This could mean your host’s database server is down.

Are you sure you have the correct username and password?
Are you sure that you have typed the correct hostname?
Are you sure that the database server is running?

Well, it seem I´m at least getting close to the finnish, since it´s written in the wordpress-font and everything.

Yup, I´m sure I´ve gotten the username and password correct and the database is surely running so it must be the hostname. In the file wp-config I haven´t typed anything as Mysql-hostname so that´s it, right?

What exactly am I supposed to write? I know how sensitive these things are. All though I´m not sure this is relevant, and at the risk of making myself look childlike dumb, my webhost, or serverprovider, or whatever its titel is, is 000webhost.com

I´ve never made a site before and I´m not sure how anything at all works…