1. upload osclass 3.1 to your server
2. change config-sample.php to config.php
3. put your db info
4. ulpoad 1. struct.sql , 2. basic_data.sql , 3. pages.sql. You find this file on /oc-includes/osclass/installer
5. run on your browser site.com/oc-includes/osclass/installer
6. At db, user, host, prefix, password leave blank and Next.
7. complete data in this step. admin pass, e-mail and title to the site and next
8. login to your site.
For me work this solution