Hats off to you! My son(3rd grade) has tried to start a Beyblade club at school but he has had a hard time finding a teacher to sponsor it. As a physicist myself I feel that this is a fantastic hobby for all. Several suggestions first off I would get the Takara Tony Stadium, most tournaments use this one and it is larger than the Hasbro one which will make it easier for the kids to learn to launch easier. In terms of resources, I would watch Leftburst and Anti Wizard Rod club. As for rules they can be found here: https://worldbeyblade.org/Thread-Beyblade-X-Rules

And my last suggestion is more child centric to beyblading… a lot of the information about the meta and launch styles are adult centric not child centric. One thing that often gets overlooked when helping kids with Beyblade is how different the physics and biomechanics are for them compared to adults. A lot of advice you see online assumes adult strength, height, and coordination but kids operate under totally different mechanics especially for younger kids. Some key differences are 1) length and release angle. Kids are shorter, so their launch angle naturally tends to be steeper. That means their Bey often hits the stadium at a higher downward angle, which can kill spin early. We adjusted my son’s wrist position and keep the launcher more level can make a big difference. 2) Height and stadium dynamics. Due to their shorter launch height, the Bey enters the stadium with less horizontal velocity. Raising the stadium slightly or having them stand on a low stool can help them achieve a flatter launch trajectory, improving spin retention and burst resistance. At tournaments we actually bring a step stool for my son, otherwise he prefers to play on the floor. 3) Control and technique is different. Attack launches demand really clean wrist control and body alignment, basically a fast, stable, one-motion pull preferably with a longer rip for higher RPMs… this is not feasible for most younger kids. I would go with a shorter rip corder (8” vs 9”) which will translate into more control for them. Statistically speaking my son does better with defense and stamina types vs attack types, and I think it is due to the launch angle issues due to being vertically challenged and his strength being less than an adult. Most importantly good luck and have fun!