Don't understand how to solve error message

Question

I just downloaded python3 (added to PATH) and sublime editor. In sublime editor, a book I'm using tells me to put in "cmd": ["python3", "-u", "$file"], but when I enter it (control B on Windows), I get the following error message -

[WinError 2] The system cannot find the file specified [cmd: ['python3', '-u', ........

Answer 1

I think that you should put only python "filename" in the command line interface to compile your file.