Great Courses

I cannot find information on how to use my Great Courses account I started on Xfinity . . . using my PC.  The one answer I got from my previous post doesn't work and doesn't answer my question.  The only way I've been able to access Great Courses is to use the voice feature on my Xfinity remote and watch it on my TV.  Surely there is another way to get to the courses.

If I try to access great courses on their website I have no idea how to use my Xfinity Great Courses account to sign in to the great courses website.