Usage prompt not working

[Alexprox7]

I'm farily new to github and don't use it very often; that being said after downloading the requirements and running the main.py i get a whatsapp.apk, is this the final apk I'm expected to receive? running "python whatsapp_patcher/main.py -p ./WhatsApp.apk -o PatchedWhatsApp.apk" does nothing, the answer is: "python: can't open file 'C:\Users\Umberto\Desktop\Ws patch\WhatsAppPatcher\whatsapp_patcher\main.py': [Errno 2] No such file or directory".
in addition to that what is the apk in the downloads for? it doesn't appear to work; should i put it in some directory to see it chaning into something else?