You begin by preparing your surface if you want the background coloured and for the most part it looks more striking painted. Paint the entire stone, front and back and leave to dry. I tend to paint several stones at a time so that there are a couple on hand to dot. They don't usually take too long to dry and you can speed the process up using a hair dryer. One can also dot on artist pad paper or canvas's, both of which can be purchased at dollar stores, online or Michaels. You will also need a couple paper towels.
It is a good idea for your first attempt to start with the dot in the centre and work out from there. Just follow what I did above and feel free to use different colours and know that yours will probably look different than mine due to a different size stone or canvas and the different size dotting tools you use. The biggest tip is to dip your dowel and then put end of your tool perpendicular to the stone and dot straight down & watch until paint starts to squirt slightly outside the dowel and lift it straight up (there should be a little slightly raised bead in the centre & re-dip into the paint each time to do each consecutive dot or they will be an inconsistent size. It's good to try this on a piece of construction paper before doing on the stone or canvas you want to keep. You will need to wipe off the end of the dowel occasionally if it starts to get a little globby. Don't thin the paint! Let the paint dry completely before you start to do any layering. Don't try to fix mistakes until they dry then you can touch up with paint using a small paintbrush for the background (wait to dry) and then repair the dots. I haven't tried it yet but next time I get to town I am going to purchase a clear finish to spray on stones so that I can put them outside this summer. I hope you enjoy doing as much as I do.