There are a number of components to a successful OJS install: downloading and
unpacking the OJS application files in a web accessible directory on your server; creating
a separate files/ directory that is not web accessible; and most
likely, manually creating a database user and database.
All servers are different, and the installation process in your case may be
different than what follows. If any of this confuses you or for some reason does not
work, be sure to check the documentation that comes with OJS in the
docs/ folder, as well as the support forum and FAQ. But also be sure to read your service provider and server documentation
as well.