
Instead of trying to describe it, I'm going to give you the website. It also shows some beautiful examples. My attempt pales by comparison. This site has a kit with all the tools you need for $15 (not including chalk). Nothing very expensive and will last for a long, long time.
Hint: I would use old chalks as the oil will stay on them and you can't use that area for regular chalking, or make sure you use only a tiny area of your chalk.

Ask me any question in the comments. I know this isn't a good explanation.
Candy