The scheduler looks at all imported calendars, jobs, and appointments in Dubsado that are marked as BUSY.
For example, this is how a BUSY event looks in Dubsado. When set to busy, it will block out you scheduler. So this is an all day job and I am marked as BUSY.
It would cause my scheduler to be blocked out like so:
If you do not want jobs or events on synced calendars to book you out, mark them as AVAILABLE.