There are several great Wordpress plugins that offer capabilities for having a course membership site where your contents are organized: Wishlist Member, Optimize Press, Member Press, Zippy Courses (there are many more!). I'm also a fan of 3rd party hosted course platforms like Thinkific, Teachable, and Ruzuku. The number one question I ask when searching for the right course platform is, "What will the user experience be like for my students?" I look for something that has an intuitive user interface and allows the student flexibility in navigation. There are several factors to take into consideration but that is a start. Good luck!