- download the accordion module from the marketplace
- write your own accordion module(there are a ton of free accordion scripts out there. e.g. on Codepen)
Apart from this:
when you open the module in the "new" design manager you'll find the "usage snippet" in the right sidebar(at the very bottom). Simply copy it and paste it in the source view of your blog post at the desired place.
If you want to have it always at a certain place I would recomend to place it into the template. If you do so there is another tipp I can give you: Wrap the whole module Hubl/HTML code into a boolean widget. With this you'll have the module always in the template but you can decide if you need it or not 🙂