How to change default paragraph style in Pages

I wasn't asking for a critique of my design choices. I have very particular reasons for making the choices that I've made (the client wants to lay out her knitting patterns in Pages because that is the software she is accustomed to; she is quite familiar with Pages; the layout needs to be flexible, so I cannot use preformed textboxes, etc.).

I'm glad to hear that you get Body as the default text style when you create a textbox. However, I do not.

Sorry to be snippy, but this is precisely the reason I am always hesitant to pose questions on this forum. It's really frustrating when people use this as a forum for establishing a professional pecking order instead of assuming the poster might have some semblance of a clue.

That's an excellent suggestion, thank you—though I think I've figured out both where I went wrong and how to fix it, so let me share it here in case someone else encounters the same issue:

I'm used to working in InDesign, where you can name styles anything you like and then easily set any one of them as the default for new objects. So I had deleted all of the default styles in my Pages document and had created new styles with names that I knew would make more sense to my client. Peter's remarks gave me the essential clue: because I'd deleted the software's default Body style, it defaulted to the first new style I created (which was not the body text style).

Changing the name of my body text style to "Body" didn't trick Pages into thinking it was its default paragraph style, so instead I created a new text box, changed the text inside to my body text paragraph style, and then with the text box (not the text inside, but the box itself) selected, I clicked Format > Advanced > Set as Default Text Box Appearance. And now every new text box uses my body text style as the default.

And Peter, I get that many people on the forum are beginners and it's safest to assume the poster has minimal information at their disposal. I also get that tone doesn't convey very well online. However, I did mention that I am experienced in page layout, and I think the syntax of my question indicated that I am not a total noob. I appreciate your wanting to offer advice—from the number of posts you've made you are clearly very generous with your time and expertise. It's not so much the offering of advice beyond the scope of my question that rankled me, but rather its tone. ("I wouldn't do this..." "Why are you doing that..." "What you are doing will cause your client frustration.")

Thank you for offering to look at my files and to help me anyway, and I do see your point about providing text boxes with Placeholder text. I've tried this with other clients and just ended up fielding questions in the opposite direction. ("Do the boxes have to stay here, or can I move them?" "What if my text doesn't fit into the boxes you've made; is it OK to make another?" Etc.) I find that either way, you're going to get questions when you create a template for a client who has less experience with page layout.