I've been trying to install packages using terminal but I keep getting errors and it turns out my sources.list file is really messed up.
So I found this webstite that generates a sources.list file for you
I know my country and my release but I have no idea what other boxes are supposed to be ticked or not because I don't know what they mean.
My overall goal is just to have an up-to-date version of Ubuntu that is able to have Player, Stage and ROS installed on it.