These are very comprehensive and instructive:
This SITE==== https://www.grammarbook.com/english_rules.asp is great for explaining all the various punctuation marks and their usage, plus more grammar explanation.
This SITE==== http://www.be-a-better-writer.com/punctuate-dialogue.html has a very clear and comprehensive explanation of how to correctly punctuate dialogue.
This SITE==== https://www.thepunctuationguide.com/british-versus-american-style.html clearly explains the differences between US and UK writing punctuation and also gives other, pertinent info.
These related SITES==== https://www.chompchomp.com/rules.htm and http://www.chompchomp.com/terms.htm have rules every good writer should know; explore them and learn.
Admin