Creating a drop down menu that links to the same page

Hi Squarespace Family,

 so I am using the Squarespace Version 7.0– Brine family (Mojave template).

I created a drop down menu with links on the navagation bar which I intended for them all to scroll down to a certain section of the same page. 

For Example

you hold your mouse on It drops down

About Us >

                  > Founders (click link is #founders)

                  >Lineage (click link is #lineage)

                  >Centre(click link is #centre)

My so when I mouse over About us and click founders, it scrolls down the same page and goes to the Founders sections. Which is what I want.

The problem I have is when I click on the main "About Us" button it goes to a dead page but I want to also direct that to the first part of the About us section on the same main page which would be "#founders" section without it leaving the main page, it doesnt allow me to put #founders in the Url Slug. It gives me an error saying that Couldn't update collection. Invalid Url.

How do I fix this problem?

Thank you.