Install captcha in community builder

Hi, I am using community builder form for registration on my joomla site.I got the keys from google but I just don´t know where to put the code they give me. I don´t see the normal html structure, so I have no head label?How can I integrate my captcha into community builder? -- You received this message because you are subscribed to the Google Groups "reCAPTCHA" group. To unsubscribe from this group and stop receiving emails from it, send an email to recaptcha+unsubscribe@googlegroups.com. To post to this group, send email to recaptcha@googlegroups.com. Visit this group at http://bit.ly/1dkFnYd. For more options, visit http://bit.ly/P65DvS.