Loopstudio Landing page

This is my first project using SCSS. Although i am not comfortable using this framework is do love how you are able to split everything up into diferent files and cant wait to get better. I do have a couple of questions involving SCSS

What folder structure should i use when working with SCSS ?

is there a difference between SASS and SCSS and wich one should i learn ?

Once i get better with SCSS i want to learn REACT. So does SCSS and REACT work well together or should you use CSS when working with REACT.

Feel free to give me tips!