Changing to static home page

I currently use a free WordPress theme (sparkling).

The “home”page is my blog and a customised home page was created for the menu.

I now want to change to static home page with a separate blog page (currently the customised home page).

When I change the settings in Reading nothing happens. I have tried creating a new Home page and adding it to the menu – after changing the current home page to Blog.

What am I missing?