Managed Rules for AWS

1) K21015971 states that the WAF rules are automatically updated, but it's not clear if that means the rule group is updated and still must be manually applied to AWS WAF, or once subscribed to the F5 Managed rules, are the managed rules automatically applied to WAF (and take effect immediately without any other intervention required to deploy them)?

2) How often are the rules updated? Is it variable and dependent on when new attack signatures are identified? Can it be several times a day or is it on a schedule? Are there any specifics around the frequency of updates beyond the statement "they are automatically updated"?

https://support.f5.com/csp/article/K21015971

Thanks!