Enabling New Drupal Themes and Modules
After you install your new theme or module, Drupal will see it and display it in your theme list or module list. After Drupal downloads and installs the theme or module, however, you still have to enable it before you can use it on your site.
In the example, the Marinelli theme was downloaded from a link on the drupal.org site under Themes. It was automatically installed.
To enable a theme, follow these steps:
On your Dashboard menu bar, click the Appearance link.
The themes are in alphabetical order; disabled themes are at the bottom of the page, so the new one, Marinelli, is near the bottom of the list.
Click the Enable and Set Default link under the new theme.
The new theme is now being used.
To enable a new module, click the Modules button at the top of the Dashboard menu bar. Because you can run multiple modules at once, there is no default option. Select the Enabled check box next to your new module and then click the Save Configuration button at the bottom of the page.