What is the first piece I should move as a novice chess player when beginning the game on the white side as a defensive strategy?
There is no magical move that will solve your opening problems. But if you learn opening principles you can find the correct moves for solving your problems your own.
I recommend you to read this: http://www.chess.com/article/view/the-principles-of-the-opening
I also found this video quite entertaining: https://www.youtube.com/watch?v=lNO9KCloLRE
Also check these opening traps: https://en.wikipedia.org/wiki/List_of_chess_traps
If you want to play "defensively" as White, start with 1. Nf3. a) This develops a piece. b) It delays moving a pawn, and gives Black a chance to "commit" first. c) It prevents Black from playing e5 without further preparation. d) It starts preparing for castling king side.
Your next move is to move a pawn, probably g3. Then move the light squared bishop to g2. Then you can castle, O-O, with a maximally secure king side, protected by both a knight and a bishop.
It depends.There are tons of openings and tons of variations that arise from them. So you may want to learn openings first to know what and what you might be comfortable with. Check out http://www.chessfiles.com/openings.html for openings and variations. They are available in PGN format as well if you want to use it with a GUI. Have fun