Blackout curtains with a snake on hooks and tulle for skylights.
In the scene there is a simplified model of a window in the wall at an angle.
The color of the model is easily changed in the material settings.

https://3dsky.org/collection/shared/5255126  a collection of my curtains

For Corona render, it is recommended to install a version at least 1.5, since the glossiness of the materials is configured with PBR in mind.

If you are working on a V-Ray version lower than 3.1, then be careful, Microfaset GTR ( GGX) is listed in the materials in the BRDF section, if your version is older, then the BRDF field will be empty. Choose Blinn, Phong or Ward – which is preferable for you.