If you have an idea where to put this: DO IT!
Make sure that python2 and the following modules are installed.
On archlinux: sudo pacman -S python2 python2-lxml python2-cheetah
sudo pacman -S python2 python2-lxml python2-cheetah
Subsequently you are ready to install and run GNU Radio.
GNU Radio on archlinux: sudo pacman -S gnuradio gnuradio-companion
sudo pacman -S gnuradio gnuradio-companion
Now you should be able to run GNU Radio in your terminal. gnuradio-companion
gnuradio-companion