Compilers in SASS
To convert the code, special programs compilers are used. There are quite a few such programs and you can choose one of them to your taste. To begin with, I suggest you use one of the following programs: Koala or Prepros.
You can also use the online compiler SASSmeister, where on the left we will write in SCSS, and on the right it will compile the code into CSS. However, it is worth remembering that it is certainly not suitable for real work.
Install one of the suggested programs.