How do I force Pycharm to recognize and use Python 3.6.1 libraries?

Same as above. Recently I broke my system and then wiped and reinstalled. I initially managed to get python 3.6 working in Pycharm with a new installed before breaking things again. I didn't do anything special and merely retraced my steps only to find Pycharm only seeing 2.7 and 3.5 instead of 3.6 on my 3rd install. I want to make use of the most current version of Python due to the features it's released. How do I set up environment variables to recognize 3.6.1 for development purposes? I did it a few times on Windows but merely went into Advanced system settings and added a few lines in a window. I installed Python 3.6.1 successfully on Mint; How can I duplicate the above process for Pycharm on Linux?