How to install Steel String to the Bridge of the Acoustic Guitar

Once you've removed the old strings, you’re ready to put on a new one. The methods for stringing a guitar diverge slightly, depending on the type of guitar you have. Fortunately, steel-string acoustic guitars are easier to string than classicals or electrics. You have two places to attach your new string: the bridge and the headstock.
Acoustic guitars have a bridge with six holes leading to the inside of the guitar. To attach a new string to the bridge:

Remove the old string (if you haven't already) and pop out the bridge pin.

Bridge pins sometimes stick, so you may need to use a tool to pry it out. The best tool for this is the notched edge in a peg winder or needle-nose pliers. You can use a flat tool like a table knife, but be careful not to ding the wood.

Place the end of the new string that has a little brass ring (called a ball) inside the hole that held the bridge pin.

Just stuff it down the hole a couple of inches. (How far isn’t critical, because you’re going to pull it up soon.)

Wedge the bridge pin firmly back in the hole with the slot facing forward (toward the nut).

The slot provides a channel for the string to get out.

Pull gently on the string until the ball rests against the bottom of the pin.

Keep your thumb or finger on the pin so that it doesn’t pop out and disappear into the abyss.

Be careful not to kink the string as you pull it.