once you have purchased wpoptins 2.0 you can download the plugin from your  MegaMarketingTools Control Center.

You can access your control center by clicking here    once you are logged into your control center you will see a blue menu  (see image)menu

Hoover over the products/services  and click my services  your services will be displayed look for the WordPress -Optins 2.0 Multi-Site License  see image bellow

products

Click view Details this will display the product Details