How to add separate navigation drop down or links on a specific page. Squarespace use this on their about page. Could anyone point out how to do that?

Site URL: https://hexahedron-soybean-zdl8.squarespace.com/

Hi,

I am trying to build a page that has its own navigation specific to that page. The main site navigation should also be available on this page. Squarespace use this approach on their About Us page (see screenshot attached). If anyone could point me in the direction to get this structure built that would be much appreciated.

It seems that on mobile these links on the squarespace site turn into a scrollable drop down menu. Mobile functionality would be great to have as well.

This is my site

https://hexahedron-soybean-zdl8.squarespace.com/

Password: testing123

Thanks in advance.

Jon