Sync issues and busy/free time between iCloud Calendar and Acuity

I use Acuity scheduling for my clients to book time with me. Acuity syncs with my iCloud Calendar. I am not able to put events on my iCloud calendar (e.g., people visiting, all day events, etc) and show the time as free. Like in Exchange you can show an event as free even though your calendar has an event listed. How can I do that?