Sharing with you some useful articles (how-to) for creating online courses for selling:
1. https://www.ispringsolutions.com/blog/how-to-create-online-course - Complete Guide on Course Development by Michael Sheyahshe, he has over 2 decades of experience in the design and development interactive media, tools, simulations.
2. https://www.ispringsolutions.com/blog/making-your-online-course-interactive - HowTo Guide on 'How to make online course interactive' by Helen Colman, instructional designer of iSpring
3.Also, i wrote that article on dev.to about eLearning standards, hope it helps some: https://dev.to/cheekylearner/elearning-standards-comparison-aicc-vs-scorm-vs-xapi-vs-cmi5-2kco

About tools you can check comprehensive guide here: https://www.ispringsolutions.com/blog/html5-authoring-tools

And if you have a questions - i will glad to answer on it!