All related information for that sentence should go in the same paragraph. That person who's speaking owns that paragraph. Everything in that paragraph is what they're doing, what they're thinking, what they're saying. No one else.I want to expand on that thought. Not only is the person speaking in charge of that paragraph, but if there is no dialogue, only one person can own that paragraph. So the person thinking also owns it.
There's a famous author out there who does the following:
"She's brilliant," Jane said. She was so certain she was right, but Ralph whipped out his checkbook and knew he was in charge. "She might be brilliant but I'm richer."
Notice how there are TWO people here who own it? Jane's speaking yet we're in Ralph's 'head' because he knew he was in charge. He's even speaking at the end, but it's not obvious to the reader, since Jane was speaking at the beginning.
Even though this author is famous, the way she writes this is wrong. It should be:
"She's brilliant," Jane said.
She was so certain she was right, but Ralph whipped out his checkbook and knew he was in charge. "She might be brilliant but I'm richer."
Two paragraphs (I divided them by a blank line), because Jane is speaking in one and owns that paragraph, while Ralph is thinking in another and owns that one. We're in Ralph's point of view for this scene. The part that states 'she was so certain she was right' is in Ralph's thoughts. The comment at the end is Ralph's, because it's HIS paragraph.
It's easy once you figure it out. One character owns every paragraph.
Have a great day!