How do you build a mansion?

What are the steps for a Mansion?

The button "Turn into HQ" is greyed out for any of my squares I click on.

I have looked all through the menus and am not able to find any element that would initiate mansions

I have 6 gang points out of 100 and have a gang level of "-"

Thanks in advance

Hello,

To build an HQ you need gang level1. And to build a mansion you need level 2.
You must build a mansion on an HQ.