opening

What do you mean defending position?

If you mean playing as black

Against 1.e4, it's pirc defense, against 1.d4 it's king's Indian defense.

This kind of set up gives up the whole center, you have to understand many complicated strategy and tactical ideas to play it successfully. I think following opening principles is good enough for beginners, playing into the center is easier than giving up the center. If you want to learn openings I suggest learning openings that fight for the center immediately. like 1.e4 e5 or 1.d4 d5. As white the best thing you can play is Queen's Gambit in my opinion as white, only 2 moves to remember.

That is far too vague a question. You need to be more specific.