php - Implementing a curl to validated server for Google reCaptcha

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I have a previous question here: Adding ReCaptcha

I received a reply directing me to this conversation: How to validate Google reCAPTCHA v3 on server side?

I guess I'm a little confused on how to implement the curl and validate. Do I need to create a verify-this.php file and add the curl code listed here: How to validate Google reCAPTCHA v3 on server side? and then upload to my server? Then what do I do to validate?

Does this have to be connected somehow to my existing test form listed here? https://www.queensmaidcleaningservice.com/test.html

Once validated, will it react the same to other forms on the site? I guess I'm a little confused on how this works. I would, however really like to know how to do this for future websites. Any suggestions or help on this would be greatly appreciated:) Thank you!