Olly,
nothing wrong being a beginner, we were all one
On your RPi3, you mentioned:
domi just put Ubuntu mate so I'm going to assume that your PI is up and running.
Is your PI connected connected to a monitor and have a keyboard/mouse plugged in to it?
Is your PI on your network (as in: can you ping google.com)?
If yes to all of that, then open up a terminal (you'll find that somewhere from the start menu in Ubuntu or maybe there is a shortcut on the desktop).
In the terminal type:
sudo apt-add-repository ppa:mutlaqja/ppa
then
sudo apt-get update && sudo apt-get install indi-full
If you the PI is not connected to a monitor, then you'll have to SSH to it using a software called
Putty
.
The problem is that without knowing the IP address of the PI, that's going to be difficult, so you'll have to find out somehow which IP the PI is setup with.
Many tutorials online for this.
ie:
thepihut.com/blogs/raspberry-pi-tutorial...ess-the-command-line