Modal Window Close Button

Dear Noda and Team,
I’ve created a modal window in Highend and wanted to add a button that has the function to close the modal window (=same function as the X in the top right corner)

my short code looks like this:
[button title=”Continue Booking” link=”#” new_tab=”no” color=”carrot” class=”modal-button”]

my html looks like this:
<div class=”modal-button”>Continue Booking</div>

What should I change, to make this button closes the modal window?
I’m looking forward to hearing back from you.