Firstly, I do not know how to install it on Windows 10 laptop.
It uses Maven.
Secondly, as there is no documentation for this package, I want to know how to discover what all can be done with this package and how?
There is documentation for this package, and this API. Check out the README.md ...
With your above command you install java in your home directory. If the software is not explicitly required to be available to only this single user, I'd recommend to stick to the official filesystem hierarchy ( for example see here for a basic explanation The Linux Directory Structure, Explained ).
Since Oracle Java is a prime example for "proprietary ...
You appear to be setting JAVA_HOME and PATH only in the current terminal session.
You should adjust your JAVA_HOME and PATH variable in either .bashrc or .bash_profile in your home directory. Then maybe logout and back in. That way the PATH will be adjusted every time you open a new terminal.
You can try to restore your Desktop folder:
First Delete the .idea directory - this belongs to Android Studio.
Second recreate Desktop.ini:
Open the Desktop folder in Explorer exactly as you have shown on your screen shot.
In the address bar is shown This PC -> Desktop klick in the free space right to the text Desktop and type cmd and press Return key