Trouble downloading packages

[Richard Mayo]

  I say chaps,
    Having a spot of bother installing some packages.

>>  pkg install C:/Users/Richard/Downloads/symbolic-2.2.4.tar.gz
configure: error: Failed to find Python
checking for sort... /usr/bin/sort
checking for GNU coreutils... yes
checking for python... no

pkg: error running the configure script for symbolic.

>> pkg install C:/Users/Richard/Downloads/fftw-3.3.4.tar.gz
package is missing file: DESCRIPTION
error: called from 'verify_directory' in file 
D:\Octave\Octave-4.0.0\share\octave\4.0.0\m\pkg\private\verify_directory.m 
near line 30, column 7

I tried sticking in a stub file named DESCRIPTION but it actually needs it.
All help gratefully received.

TTFN
    Richard.