superpurple11; Hi ! My Welcome to the forum.
In order for us to assist you you must follow the directives given - entirely and exactly.
To that end is the instructions to do so;
Post all requested outputs between code tags:
code tag tutorial:
And show us the outputs of terminal ( ctl + alt + t ) commands:
So we can see where you are at, and where you are going. Anything you do not understand or have questions regarding, we are more than glad to expound and explain.
cat -n /etc/apt/sources.list
tail -v -n +1 /etc/apt/sources.list.d/*