Did you not have CB installed already when you installed DT Register? The easiest thing to do is to have CB already there, then when DT Register is installed, it detects CB and then adds the necessary profile fields. Then this data can be used to auto-populate form fields. Of course, users have to input their profile data for that to work
If you are just now adding CB to your site, you could uninstall DT Register (you will not lose settings, event info or records). Then install CB, then reinstall DT Register. You should then have added profile fields in CB and two new tabs. You can also install our CB plugin to show records in the user profile.
Be sure to enable CB Integration in the DT Register settings when this is all done, then also set the config of CB to use First Name / Last Name instead of the default Full Name. Hope this is helpful...