Dialogue punctuation is the same as expositive narrative.
The difference is you are marking when a person is SPEAKING, versus thinking or merely observing. From rules to execution. Here's a dialogue that hits most of the combinations and shows action, description, gestures, and tags. I was sitting at the breakfast table when my little brother Joey walked into the kitchen rubbing sleepy eyes and scratching at his stomach through his ewok pajamas. "'Morning," I greeted with a cheesy smile. My little brother is *not* a morning person, so beaming at him has the same annoyance factor as a poke in the ribs.
A privilege of being a big sister that I leverage with amusement. "Hey," he mutters in return. He climbs into his chair and scowls at the pea placed in the center of an otherwise empty plate. He grips his fork in an aggressive 'be-glad-to-poke-you' style. "Cass, what's this?" "What's what?" I respond, imagining a halo over my head. "That," he responds, casting a dirty look at the innocent pea.
I tilted my head and blinked. "It's breakfast." "No, it's not!" he snapped, bouncing in his chair. "For people who show up to breakfast an hour late it is." I made that scene up for this post, but I want people learning writing to see all the mechanics going on. How much is said with what isn't said. I didn't put a lot of scene setting here. Even though I don't describe Joey and Cass...
I bet they seem kinda authentic. The big sister picking on the brother... all the little tropes and then notice... it's not FLAT ... there's *attitude*. Here's posts : Dialogue Formatting Great Dialogue