• Install the plugin using community builder plugin interface.
• Go to GB plugin management and configure the plugin.
• The first option in CB reCaptcha is what type of widget you want to use. There are two options: reCaptcha (service provided by Google) or myCaptcha (generated on your server, GD graphics library must be installed on your server).

Params for reCaptcha mode

• Enter your public and private key from http://www.google.com/recaptcha.
• Optional: set the language and theme of reCaptcha widget. The language's code must be in two letters format: en for english, es for spanish, pt for portuguese, etc.
• Use SSL connection to reCaptcha server. If you display reCaptcha in a page over SSL, you must be sure to set this to true.

Params for myCaptcha mode

• All the params for myCaptcha mode make reference to image colours and size. I think those params don't need explanation as they are really easy to use. If you have any question visit the discussion group.

• Save the configuration and plubish CB reCapthca plugin.
• After plugin configuration, go to CB tab management, and publish CB reCaptcha tab. Here you can set the order on registration form.
• Now you (and all of your visitors) will have to enter the security code to proceed with registration or password/username reminder.