Making dropdown menu from quick booking lightbox more than 7 days


I am wondering how to make one of my dropdown menus longer than the 7 days the dropdown menu currently shows.

I have also considered changing my dropdown menu to a clickable calendar so more than just 7 days are showing, but when I do that, I don’t know how to update my coding to the correct code to get my available times to sync up with each day that is selected on the clickable calendar.

I’ve attached a screenshot to show you what dropdown menu I am referring to. The data pulled from the date dropdown and the time dropdown are directly tied into my available times for the bookings page on my site. I would actually rather switch the dropdown menu to a clickable calendar, but when I’ve swapped the dropdown menu to the clickable calendar, I don’t know what code I need added to get the date and time dropdown to sync up with my bookings page.

I am a complete newbie when it comes to coding so I apologize if I didn’t explain everything well enough. For reference, I used the instructions on this help page to code this current lightbox:

Thank you in advance.