not clear description in INSTALLER.txt

There is this text in INSTALLER.txt:
Next you need to add a new group we'll call 'magick':
    sudo groupadd magick

But in what kind of folder?
Do I have to be in directory into the magick-rotation folder?

I did in Lubuntu exactly the description, but with 'groups' there is no group "magick".
I did:
sudo groupadd magick
Then I did:
sudo gpasswd -a <your username> magick
(I replaced of course <your username> by my username)