Note: you should buy SSL certificate from your hosting provider and ask them to install it for facebook website folder before install facebook template to the server. It's Facebook requirement for each app. Please follow this link to find more details.
1. Create New App
Visit https://developers.facebook.com find App tab and search option to Add a New App.
Then select Facebook Canvas Platform to get started
Skip a quickstart
Next type an App Name (This can be anything you want, the name you are
going to call your tab would be a good choice), Select the Cetegory Apps for Pages and click Create App.
2. Configure your App
Please go to settings tab and add platforms: App On Facebook and Page Tab one by one.
Please refer to image below and read a description after it:
Canvas URL - http://yourwebsiteURL/ (you should type your website URL with http connection )
Secure Canvas URL - https://yourwebsiteURL/ (you should type your website URL with https connection)
Canvas Width & Canvas Height must be set to Fluid to fit facebook timeline view
Page Tab URL - http://yourwebsiteURL/ (you should type your website URL with http connection )
Secure Page Tab URL - https://yourwebsiteURL/ (you should type your website URL with https connection)
*** Make sure all your URLs end in / ***
Page Tab Name - Enter whatever you want your tab name to be
Page Tab Image - You can upload the icon for your tab.
After you finish entering those fields click the Save Changes button.
In order to make you app live so that your visitors could see application you should enable it in Status&Review tab
3. Install your new App to your Page
Please copy this URL http://www.facebook.com/add.php?api_key=YOURAPPID&pages and paste to your browser address bar without following this link. Then replace YOURAPPID (part of link) with your own App ID and go that link. Your own App ID is at the top of App Settings page.
Select the page you would like to install the tab on. Visit your Fan (business) Page and find there your tab.