Martial Arts Drills are an old school way of teaching … I'm not saying that it does not work but I know there are better ways to teach your martial art skills to kids (and adults).
Drills are the most basic way of learning a new skill. It is shown to the students as a simple movement and then they are told to repeat it … A LOT! That can work with adults but when you try it with kids you'll be lucky to get them doing it 5x in a row without getting bored and distracted and start talking or doing something else.
The problem with drills is that they are monotonous, it is learning by repetition. Another problem is that although the students may learn the basic skill they do not learn how to apply it in a realistic situation. As a simple example, we all know how easy it is to block a punch when you know what punch is coming, your attacker only strikes from one position and you do not need to move your own feet because because you are comfortable with how the martial arts drill will work.
It works the same way every time and it is predictable which also makes it boring.
The alternative is practicing new skills by using games that incorporated the new technique. In a game environment things are much more dynamic. For the example of learning to block a martial arts game like "The Mummies Return" allows the students to practice their blocking skills in a more active arena. The skill is the same but now they are being approached from different angles and they have to move their feet to position themselves correctly for the incoming attack.
Everything is still monitored by the Instructor so nothing gets out of control, but it is a whole lot more fun for the kids and they learn how to really apply the barriers in a much more realistic situation.
My suggestion for teaching a new skill is to show the class and run through the technique as a martial arts drill for a max of 10x repetitions and then get them to apply it in a martial arts game. They will immediately understand why they need to do a skill a certain way. When you practice in the air you get no feedback and can be doing it completely wrong, but when you have someone coming at you everything makes sense and you learn how to make adjustments to quickly improve the technique.
So do not get me wrong, drills are still needed but only as an introduction to using a martial arts game to show it's real application. I hope this helps you plan your lessons to include some martial arts games for kids.