As for blocking out days you don't want to work, the easiest way to do this is actually through your substitute-service page (such as Aesop, SmartFindExpress, or Subfinder). Below is the link for Aesop that explains exactly how to set 'non work day' on your Aesop calendar either for a one-time event, or for recurring days of the week that don't work for you. By setting it on your Aesop calendar, you won't receive available jobs for those days, and thus Sub Sidekick won't alert you either.

For other substitute services, contact the service directly to find how to set 'non work days.'