There is much that is said, and more that is assumed.
The Linux terminal can be opened by using the Ctrl-Alt-T shortcut. From there, one could type "python" or, ideally, "python3" to enter the python environment within the terminal window.
It is not practical to install modules at this point.
You can type "help", and then "help(modules)" to get a complete listing of all modules that are currently installed in your machine's Python environment. But you cannot install using pip. It will error.
Close the terminal window and open a new terminal.
In this following example, I am wanting to install the Google api modules:
Look at the first command:
I dived straight in and used "python3" to invoke the "ensurepip" module to make things a little smoother. NOTE that I did NOT enter the python environment - this is a command at the top, primary command level within the terminal.
same as for the second command:
This is the command as directed on the Google Quick Start page. NOTE that as with using the "python3" command I used "pip3", NOT the traditional "pip" module.
Note that the terminal goes into action instantly - making the connection, downloading and then installing the modules:
Downloaded and successfully installed.