Create a page. Make it available in the navigation or via some button/link on another existing page. Add a datagrig and select the location entity as database source. You can aute create the newedit page by right clicking on the new/edit button and say generate pages.

That is he easiest way to do it. If you need more logic or custom styling, you can add it.

I highly recommend doing some of the basic mendix learning paths. Everything is explained ther. You find them in the academy section.