This is a Drupal module aimed to provide licensing features for the filefield (http://drupal.org/project/filefield) and imagefield (http://drupal.org/project/imagefield) modules. It depends on https://github.com/zeropaper/license
Put it in the modules folder of your choice and enable it from the admin/build/modules page. That's it.
Once activated the module provides additional settings for the field configuration form. I guess that if you found this module, you should be able to figure out how it works... otherwise, either you should open your eyes or the module should be improved (probably the second choice ;) )