In your calendar account (the one you linked with Blossom), create an event and ensure that it has been marked as busy.

Events will sync to Blossom app in real-time and note the blocked time as unavailable for your clients.

Note: Outlook users tend to experience delays or issues due to how Outlook syncs with 3rd party APIs. If you are using an outlook email address and experiencing technical issues, please contact support@blossom.team.