All I understood from your small description is, you haven’t installed the python on your machine yet. Assuming, you are using a windows based machine. First of all, go to python’s official website and install the .exe file (the latest one if possible)after downloading it.
After doing this you may open your PyCharm now and find the settings option.
Then search for Python Interpreters from the directory of earlier installed Python.
Now you are ready to rock