1.) Follow the Language-specific instruction for integrating the Nitro-LM client libraries into your application. The client libraries and example applications are available from http://download.nitrolm.com/.
2.) Test demo licenses and any other Nitro-LM features you've integrated into your application. When a demo license has expired, it's a good practice to launch a website where the user can purchase your application. This can be either your website, or our paypal.html link with the &sbx=1 removed. By integrating a demo license process into your application, you'll already have their lmemail to send along to the paypal.html url as a parameter.
3.) Once you're comfortable that the system is working well with the PayPal Sandbox environment, update your URLs to remove the &sbx=1 parameter and modify your Price Configurations to set your actual PayPal seller email address.
4.) Deploy your application, market it well, then sit back, relax... profit.