It’s a little difficult to track down the setting that controls this, but in order to get a category’s subcategories to show on the hamburger menu, you will need to change a setting in the relevant category. Here are the steps:
- Navigate to the parent category
- Click on the
button to open the category settings - Go to the Settings section of the window
- Uncheck the setting called
Show subcategory list above topics in this category.
You will need to do this for each category in order to show its subcategories on the hamburger menu.
Let me know if you need me to clarify anything 