If you are applying paint, you need a clean surface to start with. Dust and dirt under the paint will cause problems with adhesion and you will end up with flaky paint. Wipe each stone down with soap and water. Then, wipe each stone down with a rag dipped either in water, acetone, or isopropyl alcohol. Let the stones dry before applying paint. You can apply glow-in-the-dark paint in 2 common ways. You can buy spray paint and spray the stones, or you can brush the paint on. If you use spray paint, follow the directions on the can regarding time between coats and the distance the nozzle should be from the stone. If you use a brush on paint, make sure that you follow instructions regarding the drying time between coats. Once the paint has been applied, it will need to dry. The final dry (known as curing) will take longer than the dry times between your coats. This is because all of the solvent (the chemicals that keep the paint in liquid form) must evaporate. Avoid smudging the paint or getting it dirty before the curing process is over. Depending on the type of paint used, curing can take anywhere from several minutes to hours. Consult the instructions on the can. Find a good location to place your glow in the dark stones. Keep in mind that any night time lights (e.g. a porch light) will make the glow less prominent. For the most impressive glow, put the stones in a dark, open path (e.g. through a garden). Once your paint has cured, let the stone sit in the sun all day. The paint should absorb energy from the sun. It will slowly release this energy as light (much less intense than the original sunlight), which you will be able to see in the dark. Street lights and yard lights may make the stones seem less impressive.

TL;DR in Vietnamese:
Làm sạch đá. Sơn đá. Chờ sơn khô. Lát đá. Quan sát các phiến đá trong đêm.