Below are some websites to help better explain cyberbullying, what to do if it happening to you or your child, and how to help prevent it from happening.
https://raisingchildren.net.au/pre-teens/behaviour/bullying/about-cyberbullying
https://childmind.org/article/help-kids-deal-cyberbullying/
https://www.understood.org/articles/en/cyberbullying-what-you-need-to-know