Ive been looking over the 'How To Change Your Guitar String' guides and they are pretty good, besides when they lock their strings. We do this to keep the string from slipping and going out of tune.

This is what a properly locked string should look like. Essentially you wrap it around and bend it over itself

I change my strings once every 2 to 4 weeks, as i play my guitar 4 or 5 days a week, for several hours. There are ways to prolong said string longevity. Ill talk about that another time.

Thats it! So simple. I also stretch out my guitar strings after i put them on to pre bend the strings cause i hate when my guitar goes out of tune. Good luck!