You create a form by Google Form with your email account.
Open your calendar and add some events to it. ( make sure you created event with a same account which you created Form )
Back to your Form, you click to the setting icon and click to “collect email address”. A booking form must have that information to send the sender notification.
After doing step 1 to 3, you have to add the Booking Calendar add-ons to your form. To do this, you click to the “more” icon Then, find the Booking Calendar in the “search add-ons” section. Find the Booking calendar and once you find it, click it and press “install”. After you have allow BC to use your information, you can now find BC by clicking the icon and see the Booking Calendar here.
To use BC, press the "puzzle" icon and select Booking Calendar. It will open a window named Booking Calendar. Please choose “Configure Booking Calendar”. After selected this, you will see a small box
Please select “Dropdown “ in the “multiple choice” section and make adjustments to your form.
Choose your calendar for your Form. ( only 1 Calendar for a Form)
After you choose your calendar and press Save, systerm will automatically sync the event’s date from your calendar to the form.
You can follow these instruction.