You can follow the official Moodle documentation. Below you can find relevant information about the Bitnami configuration.
Using the Web interface
Since Moodle 2.5 you can install any plugin from the Moodle administration panel.
Using a manual upload
With this method, you need to copy and uncompress the plugin to the server file system in the correct directory. You can check that the module has been correctly installed in the “Settings -> Site administration -> Notifications” menu (as the Moodle admin user). You can disable the web installer and use an SFTP client or scp to manually copy the files.