Your terms and condition fields in CB > Field Management are losing their values on update? We don't touch terms and conditions field except the "acceptedterms" field and that's only if legacy CB 1.x configuration exists as it migrates the old configuration to the "acceptedterms" field. If you're talking about Joomlas Privacy Consent plugin in Extensions > Plugins we've no control over that.

We don't delete fields or reset their parameters in any way during install so I don't understand what your issue is. There is no code to touch terms and condition fields during install except if it's "acceptedterms" and that's only if it's migrating CB 1.x.

There is no redirect to the home page after registration. If you've CB Auto Actions installed maybe you've configured a redirect?

I need the directory of the file where the fields displayed during registration are inserted, to modify them by intervening directly on the code, thanks ... keep in mind that I always have very little time to devote to this site ...

No, you absolutely do not. Do not modify core field code. That's not how CB works; we will not help you with modification of core code.

Describe exactly what you need and we can provide the best course of action. Just sounds like you need to create a Terms and Conditions field in CB > Field Management. You can have as many Terms and Conditions fields as you like and they can be labelled however you like. They can also use a Joomla article for their terms display. Example Terms and Conditions field parameters as follows.

Output: URL
Type: Privacy Policy
URL: index.php?option=com_content&view=article&id=ARTICLE_ID_HERE&tmpl=component
Display: Modal Window

This will open a modal window when the user clicks the terms link that'll display the Joomla article with the ID supplied to ARTICLE_ID_HERE.