It can be tricky to find out how to create a customised facebook tab. To do so you need to follow these steps:
1. Create a Facebook App
2. Fill in the “App on Facebook” and “Page Tab” sections. These need to point to the hosted page. Obviously there is plenty more than can be done to make this fit your needs – but this is not the place to detail it!
3. To add the App to a Page you must be an administrator of both the App and the Page. Use the following URL and change the YOUR_APP_ID to the id of your app and all done: