Can somebody explain in simple language?

Exactly why it's advantageous to move first. I admit I know little about chess.

because u will be able to advance first and stop the opponent

This is best shown through symettry, sometimes being the first to move can make all the differance.

The person to move first will have his threats move a split second earlier, which is advantagous.  Black will have to adjust his play to meet these threats.  This advantage is mostly negligable at a 1200 level however.

Well, first of all the advantage (i.e. from being white and starting the game; I assume this is what you mean) is very small. I think you can find statistics about how big (=small) that advantage is from this site (just now I forgot where it is).

In my view the advantage stems simply from the fact that the one going first has a kind of initiative - a "lead" to which the other player (black) has to respond.

The statistics of the advantage to start (as white) is 49.4% wins versus 46.9% wins for black (see "view players" at this site)

i thought it would be mmore

 Makes sense!  Thanks!!!!!!

 I've alway heard it doesn't make much difference in lower rated games, but I was just curious about the concept.

Many decent books state that 3 tempos is worth a pawn.  So a third of a pawn to start out with is still an advantage, no matter how small.

Then there's the ability to steer the opening (to some extent!) => 1.e4 or 1.d4 can mean a difference in the kind of game you intend on playing.  

Why do you seem that hysterical?

 Because I usually don't get answers that make sense.

White has the initiative and Black must fight for equality. If White loses the initiative, i.e., plays a weak first move like 1.a3,  then Black can push a center pawn two squares (or make a hypermodern move) and be the first to compete for control of the center.

The side that best controls the center in the beginning (from the center or the flank) has the advantage, which equates to having the best chances of winning.

 Yes, usually white wants to fight for an advantage. 1.a3 (The Anderesenn (sorry about my spelling) Opening) is not too bad, as your simply playing black with the white pieces, except that a3 is already in, giving you more possiblities.

Because as Musicamole pointed out, White has the initiative, which means that Black must REACT to White's moves, which limits the moves that Black can make. The only way for Black to gain the initiative (assuming no mistakes for White) is to sacrifice material, but then if he cannot bring White to make inaccuracies while reacting, Black could have a lost game in the ending.

In many positions, having the move or not is the difference between winning and losing. It is not hard to devise a position where whoever has the move wins.

White has the advantage/initiative by having the first move. Why would White want to play as if he were Black, giving up the advantage and thus needing to fight for equality?