hi Norman,
You can do this using Layout Element’s disable elements tab – https://docs.generatepress.com/article/layout-element-overview/#disable-element
Do the FF:
1.) Create a Layout Element.
2.) Go to Disable Elements tab and check “primary navigation”
3.) You then go to the “Display Rule” tab and set the location to the page you want to remove the primary menu.
4.) Save the layout element.
This should remove the primary navigation on the page you’ve specified. 😀