Hello and welcome to our forums,
We do not have any tutorial including a licensing sample built for a VB.Net Class Library, but the implementation should be similar. You should just make sure you call either the "ReadSettingsStr" or the "ReadSettingsRetStr" function from our trial.dll when your application initializes and that you call the "DisplayRegistrationStr" function when you want to display the registration dialog of our trial.
For more details have a look on our
"Integrate Licensing support in C# or VB.NET applications" article.
All the best,
Daniel