How can I add a Delivery Option to my check out page?

I have spoken with Wix Support about assistance with the instructions for this html code: https://www.wix.com/corvid/example/Delivery-Time

I was advised to create an account in this forum community.
Wix Support has informed me that they do not assist with adding code to the site. They also confirmed that there is currently no other option to add a delivery option to the wix site outside of adjusting the code.

I need assistance with adding an option for in-person delivery and the selection of a delivery date.

Thank you.