Nothing is easy until you learn to do it. Restringing a guitar is a perfect example of that. Before you've learned, this administrative, but necessary maintenance task can be a bit daunting. After all, you don't want your guitar to play poorly, sound bad, or incur damage in the restringing process.
This video gives you a short, sweet tutorial on restringing an acoustic guitar, which will afford you the confidence of knowing you did it right. If you just want the quick-hit takeaways, you can read the basic steps written out for you below.
Begin by loosening the strings. A D'Addario Pro-Winder is great for this.
Once the strings are nice and loose, clip them near the soundhole (the Pro-Winder is also great for this).
For each string, remove the bridge pins and pull out the ball end, then unwind the other end of the string from the tuning pegs.
Replace each string by placing the ball end into the bridge pin hole and pushing the bridge pin down on top of it. Make sure the bridge pin bevel is aligned with the direction the strings run.
Thread the opposite end of the string through the tuning peg, wind a few times until it's snug, and snip the excess.
Tune the guitar to pitch—preferably with a super-accurate D'Addario Tuner.
Stretch the strings gently, using your hands to lift them upwards and away from the fretboard.