Like gate.how to do that?

Hello everyone!
I have few facebook pages and i wont to add like gate.
People have to like my page to see the main content.
Can anyone help me?How to do that?

search from facebook "Static HTML: iframe tabs", add app ad build your tab with it.

It can be used on your website but you can't do that on facebook there are few scripts thats does that like viral social locker and social locker you can give it a try.Or if you want to show them main content on app you can add a tab on facebook and iframe it with lockers .