For the plugin to work, you need to connect your website to Google reCAPTCHA. Follow these steps to get your keys for free:
Log in to the reCAPTCHA Admin Console with your Google account.
In the Label field, enter your website name (e.g., My Q2A Forum).
In reCAPTCHA Type, it's very important that you select reCAPTCHA v3 (v2 keys won't work with this plugin).
In Domains, add your website URL (e.g., yoursite.com). Do not include http:// or www. If you're testing locally, you can add localhost.
Accept the reCAPTCHA Terms of Service and click Submit.
The final screen will show you two keys:
Site Key
Secret Key
Copy both keys.
https://www.google.com/recaptcha/admin/create
It's not all about downloading and randomly hitting things. You have to read the MD readme.