This anchor chart covers the 5th grade Common Core comma rules:
Demonstrate command of the conventions of standard English capitalization, punctuation, and spelling when writing.
Use punctuation to separate items in a series.*
Use a comma to separate an introductory element from the rest of the sentence.
Use a comma to set off the words yes and no (e.g., Yes, thank you), to set off a tag question from the rest of the sentence (e.g., It’s true, isn’t it?), and to indicate direct address (e.g., Is that you, Steve?).