There are a few ways to add holds or block a date on the calendar.
From your Gigwell Calendar
Hover the "+" icon inside the desired date and select "Hold" from the drop down.
You can also create any type of states and save it to the list.
From your Gigwell Dashboard
You can create a 'manual' date from the event stream icon.
Once the date is added, change the status to blocked and select a reason from the dropdown.
Once you are ready to create a booking, you'll need to delete the manual date and create a new booking from the "New Booking" button.
From Google Calendar
If you have Google Calendar enabled for the artist, you can add it directly there.
Holds or blocks in Google Calendar will create a warning message in Gigwell if you try to create a booking for the same date.