Category Problems

Hello as you can see on the front page there is a black Categories menu.
I know how to add the categories to the menu in Apperance>Menus
See pic: https://simssublimation.com/wp-content/uploads/2020/08/Capture-1.jpg

However I do not know how to add a NEW category to the list. What is there is set as demo from the theme.
I have went to Products>Catergories and added my categories there as seen here: https://simssublimation.com/wp-content/uploads/2020/08/Capture2.jpg

As you can see in the 2 images, the categories in each one are different.
I would assume that whatever categories we entered in Products>Catergories would reflect those that are under Appearance>Menu>Catergories but it doesn’t.

The page I need help with: [log in to see the link]