Welcome to what must be my fifth horn DIY tutorial by now. To be fair this is not a full DIY from the beginning, I uploaded part one on my channel a few weeks ago. So I guess this could be considered an extension tutorial.
You can also make the basic shape of the horns using this tutorial
I know spray paints can get quite expensive, and some times a wide range of colours are hard to find, so if you can only get your hands on one colour (black) you could use nail varnish as an alternative instead. It’s not as easy, quick or effective as using spray paint, but if it’s all you have to hand then it’s perfectly achievable to get a similar effect.