wookie do you have a pc or only the pi?
Use winscp and putty ( both are windows programs ),
they can help you getting it on the pi and unzip it on a pc
https://winscp.net/eng/download.php
hostname : < your ip > port :22
User name: volumio Password: volumio
and press connect
navigate to volumio folder on the pi and drag and drop the extracted folder in to the folder volumio
now we gonna use putty and login to the pi
open putty same way to connect use ip of the pi
fill in the ip and save session now select your session and press open
and again user: volumio and pass: volumio
accept the session auth key if asked.
cd volumio
now we are in the folder volumio and run:
volumio plugin install
let it do it’s thing and your done.