Why the Center Wins Games
The simplest idea in chess
Imagine you are standing in the middle of a room. From there you can reach any wall in a step or two. Now stand in a corner: half your options vanish. Chess pieces feel the same way. A knight in the center touches up to eight squares; a knight in the corner touches two. The center is simply where your army can do the most work.
When players talk about "controlling the center," they mean the four squares right in the middle of the board. Owning that space lets your pieces flow to either side of the board quickly, while your opponent has to take the long way around.
Pawns plant the flag
You usually claim the center with a pawn or two on your very first moves. A pawn sitting in the middle is more than a blocker: it pushes the enemy pieces back and builds a little wall behind which your bishops and knights can develop in peace.
The mistake beginners make is treating the center like a trophy to grab and forget. It is not a one-time prize. The fight for those squares continues for the whole opening, and sometimes the player who gives up the center on purpose, only to strike back at it later, comes out ahead.
What to actually do
In your first few moves, put a pawn in the middle, then bring out a knight and a bishop so they aim at central squares. Do not move the same piece twice while pieces are still asleep at home. If you remember nothing else: every move in the opening should make your control of the middle a little stronger.