There will be a folder named 'The-Powder-Toy' in the directory where you cloned it.
$ git clone https://github.com/simtr/The-Powder-Toy.git
Clone it again
Just search for the folder 'The-Powder-Toy' using the search bar in the start menu. Right click and there'll be a 'Open folder in directory' option. Click dat. I think git bash opens in the default 'C:/Windows/system32'.