In general this is simple, unbolt the old fender and bolt on the new one.
Of course there will be lots of little plastic bits to remove here and there. And you might want to paint the fender to match the rest of the car. I have found that the best way to do this is to first put the new fender on and do any minor adjustments (cutting,drilling, dent removal) while it is on the car but remove it for painting. This will allow you to paint the inside and will avoid any overspray problems on the rest of the car.
Of course there will be lots of little plastic bits to remove here and there. And you might want to paint the fender to match the rest of the car. I have found that the best way to do this is to first put the new fender on and do any minor adjustments (cutting,drilling, dent removal) while it is on the car but remove it for painting. This will allow you to paint the inside and will avoid any overspray problems on the rest of the car.