Go to the Sales menu and select the Availability Grid
Select start and end dates, location, etc. as per when using the availability grid to view availability, and then search.
In the availability grid, select the dates you want to create the enquiry and booking for, in the row for the unit you wish to book.
This will open up the Enquiry view, with the dates and unit pre-selected. Proceed as per when creating an Enquiry.