Concussions are serious but often not noticed. Coaches must receive a signed Participation Release Form from the parent/guardian before a player having a concussion or suspected of having a concussion is allowed to return to play.
AYSO's concussion policy is at http://www.ayso.org/news/12-03-21/AYSO_Concussion_Policy_Announced.aspx
As noted in that policy, coaches should complete (and all others are invited to complete) the CDC course at:
Keep a copy of your certificate for later submission to AYSO.
For more information on concussions, please read the materials at:
You can also take the National Federation of High Schools "Concussion in Sports - What You Need To Know" course at:
Please note that you'll need to register first at https://www.nfhslearn.com/Registration.aspx and then you can take the 20 minute online course for free.