I am really stuck. I have been searching materials(videos/documents) that help me to install python plugin on IDA. I tried this https://github.com/idapython/src/ and followed the installation process but still IDA is unable to find python as plugin.
I am using IDA freeware and latest version of python on windows 10.
Please help me.
You don't need IDA python installed. It's already installed for you.
E.g. on OS X the path is following:
ls -1 /Applications/IDA\ Pro\ 7.1/ida.app/Contents/MacOS/python
PyQt5
ida_allins.py
ida_allins.pyc
ida_auto.py
ida_auto.pyc
ida_bytes.py
ida_bytes.pyc
...
But in your case you should know that IDA Free has no idapython included...