For instructions, see: 
https://scope10.deviantart.com/art/Penumbra-10-Windows-10-visual-style-568740374

Variants
Penumbra 10 comes with a couple of variants:

- Penumbra10: The theme as it was intended to be used. 
If you don't know which variant you should use, pick this one.

- Penumbra10w: The w stands for "White". 
This theme is like Penumbra 10, but has a white Windowcolor and black Windowtextcolor. This is meant for people that want a dark theme but not want programs like Microsoft Word to be affected with a dark page and white text. This theme does create inconsistencies with the rest of the theme.

- Penumbra10s: The s stands for "Stock". 
This theme is like Penumbra 10, but with stock/default looking caption buttons (Minimize, maximize, close) and Taskbar button.

- Penumbra10ws: A combination of White and Stock.