Your swimmer should have been told by their coach which county meet (Bronze, Silver, or Gold) they have been assigned to attend and which events they will be swimming. You (the parent) do not need to do anything to sign-up your child for the county swim meet. If you have concerns, please talk to your child's coach TODAY (Monday).
Within the next few days, a psych sheet for each county meet should be posted on the bulletin board so you can re-verify which meet and events your swimmer is swimming.