University of Maryland Global Campus. (n.d.). Lecture 5: Leadership and strategic thinking. Document posted in UMGC HCAD 600 9041 classroom, archived at http://campus.umgc.edu
No official APA format for citing online classroom materials exists - this is merely a recommended format to use in citing such documents.
If in your Discussion post you quote, paraphrase, or summarize your course module or course readings or other material you researched from the library or the Web or a print source, give an in-text citation AND a reference list citation at the end of your Discussion post in the same manner as you would within a research paper.
If you mention or refer to another student's entry/response in a Discussion post then do not cite it but simply mention the other student's entry in your sentence. Example: I agree with Susan Day (Discussion Post October 30, 2018) where she lists specific state legislatures that supported the Affordable Care Act.