Play with Docker Classroom Query

Hello,

I am new to Docker. Just searched online and like to learn.
I have started Play with Docker classroom.

When I started using it from browser, I suddenly noticed that there is some disk space getting utilized on my system.

Can someone tell me what is going on???
Does Play with Docker utilize disk space on the system?
Does it install anything on system.

I am using Windows 10 system.

Please suggest.