The configuraiton is straightforward, you will need the secret/site codes provided by Google on their website.

1. Enter the secret / site keys in the plugin settings
2. Place {% include ['_recaptcha/frontend'] %} where you wish to validate users
3. Create javascript functions that are called on success/failure

window.recaptcha_success = function(){ ... } window.recaptcha_failure = function(){ ... }

See GitHub for a full list of options and upcoming improvements.