gulp-changed | Only pass through changed files | Runtime Evironment library

Am trying to run gulp commands from package.json. But unable to execute.

This is my package.json.

I am very new to gulp and sass, but trying to create a gulpfile that will take and scss file and turn it into a css file (this seems like it is a very common thing that lots of people do). I am following along this tutorial - https://youtu.be/nusgoj74a3Y?t=1301 - but it seems to be a bit outdated.

My directory looks like this

-xxx

--gulpfile

--src

---Assets

----scss

-----default.scss

----css

My gulpfile looks like this:

In my gulfile.js, I'm using watch to compile scss files to css files. It runs without error and when I run gulp in powershell, it says that it is watching, but whenever I define a style in my scss file, it doesn't affect the css file which is created and I have to stop gulp and run it again. Actually, it's not watching carefully ! Here is my code. Thanks for any help.