To give a perfectly serious and not at all snarky answer, the first question I have is: why Turbo C? Does the course you are taking require that particular compiler/IDE (I can't imagine any other reason for using such an antique, but I know that many schools in India and Pakistan among other places have standardized on it), and if so, how did you get to your 4th semester without using it before?
OK, maybe that was a little bit snarky. But to continue: what version of Windows are you running under? This is quite relevant, as versions of Windows from Vista on will not run Turbo C (or Turbo C++, for that matter) without using a virtual machine to emulate an older edition of the operating system. It will complicate the process of installing Turbo C, but it will still be possible (sort of).
Next, do you have an actual copy of Turbo C to install? It shouldn't take more than a simple Google search to find a downloadable copy, so I'll leave it to you to get it. The installation process should be self-evident.
Assuming that you have a suitable installation of Turbo C on hand, the solution is to... run Turbo C. That's really all you need do, as it will automatically create an editing window for you. Write your program and save it, then compile. Simple.
I have one final question, however: didn't your professor explain all of this to the class?