I assume you use Ubuntu, which comes with both Python 2.7 and Python 3.5 preinstalled.
You need to distinguish between the Python GUI and Python that you can run within a bash session, aka. the black terminal window that you can start by holding down
CTRL + ALT and pressing `T
Inside the bash, you simply type
python (for version 2.7) or
python3 (for version 3.5) and this will output something like this:
Python 2.7.12 (default, Nov 19 2016, 06:48:10)
[GCC 5.4.0 20160609] on linux2
Type "help", "copyright", "credits" or "license" for more information.
You can now write code following the 3 ">>>". For example, try to write
print "hello world" (for 2.7) or
print("hello world") (for 3.5) and it will output
hello world. To leave python, just type
exit() or close the terminal window.
You don't need to set any path, everything should work out of the box unless you made changes already. You can create folders with the
mkdir command in the terminal and save your Python programs in there.
The path for Ubuntu/linux is not something you at this point need to give much thought. You should focus on understanding the basics in Python. Write simple and small programs, and store them in a folder.
If you are "lost" inside the terminal, and you need to find your Desktop for example, where you can create folders, in which you can store your .py files, you can do the following.
cd folder-name-shown-after-typing-ls (this is the name of the folder of your laptop name most likely)
You are now in a familiar place, as the Desktop is what you see when you first open Ubuntu.
Hope this will get you started on finding your way. It seems foreign at first, but it is actually very easy once you dig a bit more into it.