Styles...where are they?

I have downloaded some FormFont styes to a folder on my computer. In a SketchUp 2018 model file when I try to apply one of those styles to the model scene the folder is empty. Once out of SketchUp and opening that folder the style files appear. What might be the issue here?

Do the styles in the folder have “.style” extension after the names? eg:

Does the folder appear in your Styles window? What I do with my Styles folder is add it to “Favourites” using the blue arrow in the Styles window, then I can access it whenever I want using the dropdown menu.