It’s a known problem, that parts or all of Admin area can appear blank after installation. It is often related to the cache not being flushed in Magento. 

Follow these steps to flush the cache:

- Delete cache

If you can access admin panel:

• Go to System > Cache management
• Choose Flush Magento cache

Otherwise, delete your cache manually:

• Connect to your server with your website files over FTP/SSH
• Clear folders inside var/cache

- Log out and log back into Magento Admin.

If the extension still display blank pages, kindly contact the support for a closer investigation.