You aren't using the online booking options yet and want to redirect the "Book Now Online" button on the "Quote Send" email template to a different place.
You can change the hyperlink URL that is set for the button to any URL you would like. The go to option is to make it open a new email with some prefilled text and subject to email to you.
To edit this template go to Company>Templates and search for "Many Lines" and open "Quote Send (Many Lines) - Send Many Quotes"
Here we have two buttons to help demonstrate the two options. When the text within the box is selected you can see that the hyperlinked button at the top turns grey to show that there is an active link on that text.
The link on the Book Now Online button defaults to the ##LINK_BOOKSERVICE## merge field. To turn this into a "Create Email" button you will change the hyperlink by clicking the grey link button at the top and changing the URL to:
mailto:YOUR-EMAIL-ADDRESS-HERE?subject=Ready To Book!&body=I have made the decision to move forward with booking this service! What are the next steps?
The entire underlined text will need to be pasted into the popup box and be sure to replace the red text with the email address you want to receive the booking requests.