I don’t think there is any tutorial specific to Windows. Radiance was originally developed for Unix, and later ported to Windows. Some multiprocessing abilities were lost in the port, unfortunately.
There is a Radiance book, which is available still from Randolph Fritz. See this post.
There are also tutorials, here. @Axel_Jacobs2 wrote a nice introduction, which may be found about halfway down the page. There is also the first chapter of the aforementioned book, which is accessible through this link.
I apologize that our documentation is not better-organized. There is very good information out there and on our website, but it does require a bit of digging.
This is really a tool for advanced users, and something you might consider is DIVA or OpenStudio one of the other interfaces built to work with Radiance. The basic software you have installed has the “rad” program as a central starting point, so you can look at the man page for rad here. There is a GUI to rad, called trad, but I am not sure it is included with the Windows package. (Can someone check?)
By the way, welcome to the community. It is a struggle to get up to speed at first, and you’ll find a lot of sympathy for that.