VB.NET How to automatically process a string or file after uploading it to my website (Activation Process)?

I developed a management software and need to activate it online. I am a developer for years but new to the web development My software activation process is as the following:

a.The client gets the software     
b.The client enters the required information    
c.The infromation will be uploaded to my website    
d.The information should be automatically processed and generate a value
e.The generated value will be sent to the client to allow the software to run 
f.The client information and the activation information will inserted to mySQL 

I don't consider this method as a good method but this is my initial understanding, I welcome any suggestion to get the activation process clean, secure, and somehow easy on me as I am new to web development

I just need a guide or a method for step (d and e) I can upload and download using FTP method without problems I can eliminate all that if you gave me a better solution

sorry I didn't put any code but I am asking for something logical and I need keys to get it done.

Thank you in advance.