An unallocated booking is a booking with at least one unassigned carer - so a single carer booking with no carer assigned, or a double hander with less than two carers assigned etc.
The most "in your face" place that unallocated bookings are displayed is in the Alerts list shown on the landing page - by default they are very near the top of the list.
They are also shown in the organisation row(s) of the Plan from where they can be dragged down onto an appropriate care worker
Finally users who are in the Admin role can generate a report showing Unallocated visits by clicking Setup | Organisations, then select their organisation. From the Organisation context menu select Bookings Listing:
Set the date range etc, then 'Generate Listing'. Finally, use the care worker filter box to filter the listing to only show unallocated visits, as below:
Note users can jump straight to a particular booking from here by clicking on the blue arrow on the left of each booking.
Finally, you can save this report as a PDF or a CSV file (so you can open in Excel)