Help with GitHub repo

Hi all,
As I’m a noob where do I add my video plugin folder and then Install repo into osmc?
In kodi I paste the video plugin folder to roaming/kodi add ons
But I can’t Work out where to copy to in osmc?
Thanks in advance

Not 100% sure if I understand what you are trying to do but the addon folder is at /home/osmc/.kodi/addons

Sorry forgot to mention I’m using a raspberry Pi 3 with osmc. I’m trying to install my GitHub repo

Put it in /etc/apt/sources.list?