Change the opt-in Email to a opt-in Phone#

Question:
I used the Subscribe Form, a checkbox to Sign up for Email News. I want the same thing but for Phone# so I can send SMS text messages. It would have to set the Phone# Subscription Status field in contacts to ‘subscribed’. Also take the phone# input and save it to contacts phone#. That’s all. I created the form I need, but I need code to connect the checkbox input to the Phone-subscription-status field.

Product:
Wix Editor in Wix Core

What are you trying to achieve:
I want the customer input on a checkbox for opting in to text messages, to set the Phone subscription status field to ‘subscribed’.

What have you already tried:
I created the form with the proper fields. I do not know how to connect the checkbox, if true, to set the contact data field Phone-subscription-stats to ‘subscribed’. I’m a total beginner at this.

Additional information: