How to make this ultrasonic following project. Can anyone please help me out.

A Google search turned up Project Nemo: Project Nemo . Maybe if you 'join' the project you will get access to the design files.

That project seems to do an OK job of sensing distance but not so good at detecting direction. You might be better off with the robot luggage project from Ben Heckendorn: Make Your Suitcase Haul Itself Around with Robot Luggage! - YouTube