After buying and downloading Options Manager you can install the Component via Joomla's default Extension Installer.
In the back-end a user with Super Admin privileges can install it via:
Extensions > Manage > Install > [Upload Package File] tab > [Choose File] button >
Select the downloaded Component package and click on [Upload and Install]
After installation you should be greeted with the "Installation of the component was successful" screen:
Now the component is ready to be used: Components > Option Manager.
However before using this extension, make sure that you have a recent working backup of your website!
To enable the updates during your subscription, please add the Download Key and press [Update Key]
You can find the Download Key in the email with [db8.eu] invoice, or find it on your subscription Profile page.