I recommend that the default order or selecting the service parameters in the first step of the booking can be made custom. Admin should be able to decide in what order he wants to display these dropdowns.
Currently the order is as follows:
With a drag and drop solution admin should decide in what order he wants these elements to appear.
Also, the order should have a function in priority. When "Location" dropdown" is not the first element to choose, then but "Employee", then Employee should filter the locations, not the other way round.