Regular users cannot make layout children of layouts, but it's what needs to be done in the back end. Those were not directions for regular users but for whoever claims this one for the last bits of conversion.

If you want to try this out on your own journal, you need to make the theme layer as a child of TR, and then create the color layer you want as a user layer and then use that layer to create a style select it to use via the Your Styles page.