I'm only 66. I hope that when I get to be 70 I will still be able to learn something new.
I have already given you the exact keystrokes.
Use the same process to apply the normal style to your body text that you used to apply the Heading 2 style.
I will give you any more help you want after you have read through Shauna Kelly's beginner steps.
Basic Concepts of Microsoft Word - from Shauna Kelly
I know you can do that. It is a series of short tutorials. She put a lot of work into them. I've revised some to update them to the Ribbon versions of Word.
I have a 6-year-old grandson who loves playing a game on Grandma's phone. It has a lot of written instructions that he can't read. I read it for him and tell him that he will be happy when he can read it himself. You can read, yourself. It may still be confusing, but it gives context to a conversation.