All skis (cross country, alpine skis…) must be waxed to have a good speed on snow. The glide allows your skis to move the water (even if it is a thin film of water) out from under the base of your skis. Glide waxes are the food for the bsae, and there are different kinds of glide wax based on the temperature of the snow. Many brands have waxes, and you can choose any of them, but the waxes need to cover all the teperatures you will encounter during a season. Some have a large average use, but the glide is more efficient if it covers not too much temperature range.
For classic skis, you also need to have a grip wax (klister or kick wax) to be able to have the grip when diagonal stride. (there are also skin skis or fish scales skis, but they are they are definitely less efficient than waxable skis).
You will probably need do use apply sandpaper on you wax zone. DO NOT USE SANDPAPER if your kid has only one pair of ski for both classic/skating.
There is a waxing zone under your foot, where you apply the klister/kick wax. Even with classic skis, you still need to apply glide waxes on the tip and tail of your skis.
There are also many brands and type of klister/kick wax.
kick waxes are for fresh and thin snow, and klisters for old /wet snow. The temperature for the waxes are always written on the waxes. You can follow these to apply the right wax, based on the on temperature.
The Glide Waxes: There are glides spray/liquid to apply without iron (Just use it a few times or for races, I don’t recommend it to “feed” the bases)
Hard waxes: you crayon it on your base. If the wax is too hard, put it on the hot surface of the iron for a very short time and then crayon the wax immediately on the bsae. Keep your iron inclined on the top of the bsae, then the wax can run onto the base (better than on the floor). The layers don’t have to be too thick. Then, apply the iron on your base, start at the top of the ski and go to the bottom, with a 8-10 seconds of proceed for the whole sole. Then, wait around 10 minutes, and when the soles are cold again you can scrape it, and then brush it.
Better to use your iron at a lower temperature – 10 degrees less – (temperature written on the wax box) than a higher temperature.
Kick waxes: you apply it in thin layers (the wax zone will be crayoned in white color, and push up and down with a cork to smooth it).
If you need a base binder (when the snow is aggressive – still dry and thin snow but a bit old and groomed many times, crayon the base binder on the wax zone and iron it. Then you apply the other layers of other kick waxes on top.Always remember to clean your iron before or after a wax session.
Klisters: Apply it in diagonale strides on each side (right and left, there is a groove on the middle of your ski), and then smooth it with the palm of your hand.
After a session, you will usually have to remove your klister/kick wax with a torch or/and a wax remover (if wax remover, remove first the wax with a spatulea or paint scraper, and then apply wax remover on a rag and brush).
Remember that a ski is a very very important part of the success in competition, so you will have to take care of your gear. They must be one of your best friends ;o)