You will have to create two environment variable: PYTHONPATH and PPLPATH. The first one will be used by Python to identify a new module folder (it tells Python which folder to search for a specific module when the command import nameofthemodule is used) and the second one allows Python to identify where PPL is installed. Probably, if you are using Pyhthon for the first time this two variable will have the same content.
If you are using Linux, to create an environment variable that lives forever, update your .bash_profile file:
To check if the variable was correctly created, use env in the terminal, this command will list all existent environment variables
If you are using Windows go to:
and create the new variable pointing to the desired folder.