There are a few ways to accomplish this:
1. Adding Page Tabs with the Facebook Platform
Besides standard tabs, you can add custom page tabs with Facebook. The tab creates a page that you can enter the SKED Web Module iframe code into.
This link will guide you on how to add tabs: Adding page tabs with Facebook
2. Adding Page Tabs with third-party Apps
There are a variety of Apps out there that will allow you to add a tab for an HTML page.
This link will take you to the app center: Adding an HTML tab App
Note: Mobile custom tabs are not supported at this time and you need at least 2k Likes to install custom tabs.
This type of implementation of the SKED Web Module is beyond our customer support, but we wanted to point you in the right direction. If you need help, contact your web developer for help integrating the feature into your Facebook page.