You can hide almost every section of your store.
On the right of every section there is a toggle button enabling you to set the visibility mode as Visible and Invisible.
The Navigation visibility mode is marked in red.
In order to hide the Navigation section change the visibility toggle to Invisible (marked in red).
Click on the Preview button to see a preview.
If you are happy with the result Click on the Save button and save the changes. The buttons are located on the top right part of the page and are marked in red.