For handwashing, wet the child's hands, rub the soap bar between your hands or directly on the skin to create a soft lather, wash briefly, then rinse well. The soap is designed to rinse off easily, which is helpful for children who dislike long rinsing.
For a bath, use it the same way you would any solid cleansing bar: wet the skin, apply the lather, wash the body, and rinse thoroughly. Pay attention to skin folds and areas where dust or residue can collect, but avoid scrubbing hard. The goal is gentle cleansing, not intensive exfoliation.
Because this is a bar soap, it lasts longer if it can dry between uses. Keep it on a soap dish with drainage rather than sitting in water. For travel, a small soap box helps keep it clean and prevents it from softening in a wet bag.
Avoid contact with the eyes. If soap gets into the eyes, rinse with clean water. Use only on the outside of the body. As with any new product on a child's skin, it is sensible to try it cautiously at first and watch for any reaction, especially if the child has very dry or reactive skin. If any irritation appears, stop use and choose a gentler alternative.