how to make make secure licensing for my c# windows applicat

I'm beginner in the developement and I just developed a windowns app with c# and trying to sell it , but I don't know how to do all the licensing stuff , can someone explain to me the step by step how to do this with the way that it secure ? for example if the person change the system date then expiration date won't change or if he reinstall the app the trial won't start from beginning.

I read many articles in internet but it mostly just a code part about lisence but I need to understand what I should do step by step , and with the proper code , thank you