First Modular Program Execution | Notepad with command Prompt | Java 9

This video explains, how to execute a first Module program with the help of Command prompt and Notepad.
What is the folder structure?
What command used to compile and run the program?
you will get the answers to the above questions.
My next video will run the application with the help of tool.

[HenryLeu]

you have
java --module-path mods --module com.helle/com.hello.Hello


after the word " --module", why do you need to say "com.hello"? and then slash?
After the slash I know com.hello.Hello is the main program's package.