This is a really, really fantastic site that explains all types of writing rules (grammar, punctuation, etc) in a really clear way with examples!
https://owl.purdue.edu/owl/purdue_owl.html It’s not immediately obviously that you can navigate from a menu on the left under that video box…but other than that, I love the site! We would use it all the time at my old editing job when helping coach the authors.
Enjoy!
Sara