4) do vyhledavace (firefox) zadavam : adresa.hostuju.cz/wp a dostavam znamou hlasku:

Can’t select database

We were able to connect to the database server (which means your username and password is okay) but not able to select the adresa_hostuju_cz database.

* Are you sure it exists?
* On some systems the name of your database is prefixed with your username, so it would be like username_wordpress. Could that be the problem?

If you don't know how to setup a database you should contact your host. If all else fails you may find help at the WordPress Support Forums