Multiple Vertical Menus from the main menu (pages)

I’d like to create different vertical menus from 2 of my main menu headings.

So when I click on the Portfolio menu option (in the header) there is a vertical menu on the portfolio page

and the same for a

“Services” main menu (in the header) option. I’d like to create a different vertical menu (different from the Portfolio vertical menu)

What would be the best way to do this?