Can't make work picamera

[cavecanen]

Dear friend.
As the adeept rasptank has a very Interesting tutorial, I have been trying to explore all the possibilities and yesterday tried to make work just the camera trough the indications written in the tutorial but when I texted -sudo app.py-after install flack video streaming, an error came out: command not found.
What’s wrong?

[riderkirk]

I think you just typed in the command wrong.

You should type sudo python3 app.py if you want to run that script.