There are lots of videos for that in Youtube, even though most of them are too "professional".
But, sorry the off-topic, this it how it goes:
Buy the touch-up paint. Carefully clean the stone chip, especially wax and grease must be removed completely. Then apply the paint with a dental stick or a pencil brush that is significantly smaller than the one in the paint bottle cap, otherwise you get a bubble of the paint that's too high. Then do the same to the clearcoat (unless the paint is a one component one) and let it dry. You can apply the coat (or the one-component paint) two or three times, don't try to fill the whole cavity at once (or at all). Then very carefully wet-sand it with a very fine sandpaper and finally polish correctly. I even polished by hand since I don't have the machine tools and never used them, and a new car isn't the right one to try it the first time. Hand polishing is verry laborous and may not work well for all colours.