Python app not found

I'm trying to run a simple python script testing writing some data to a mySQL database. I've seen several different versions of instructions, one saying to create my desired folder, make that the app directory and run it; another saying that it has to be in 'public_html/cgi-bin' folder. I've tried both but when i execute the command 'python3 myfile.py' in the setup python app section i get an 'errno2 file or directory not found' error. I know the file is there because if i navigate to domain.com/appdirectory i get 'It works! Python 3.7.2' and if i navigate to domain.com/appdirectory/myfile.py i am given the option to download the file (i'll deal with protecting that or something later). What am i doing wrong?