Well, first of all, it’s very recommandable to fast the day of Achoura, plus the day before or the day after. It’s also recommandable to pray and read verses of the Coran.
Kids get benefit from that celebration to get toys and new clothes from their arents and relatives, they also play with fireworks (not very wise) and water balloons. But Achoura is not a religious celebration like Aid kebir and Aid el fitr. It’s just a commemoration of the day when Moses and his followers flew from Pharaoh’s anger. It’s important to know that it’s both a muslim and a jewish celebration, this is to prove that Muhammas (PBUH) came to finish and correct the job already done by the previous prophets.