I'm trying to get an icon theme installed, and all the guides I've read tell you to jsut copy and paste the icon folder into the /usr/share/icons/ directory, but it won't let me paste the folder and I can't extract it there either. Help?
Why can't you paste / extract there? Access denied?
If so, sudo should help out.
How would I do that? I tried opening it in the terminal but I have no clue what to type because I'm a linux noob
I recommend you read-up on on sudo: https://wiki.archlinux.org/index.php/sudo
Easiest thing for you to do is, through the command line, extract the content of the file containing your icons into the /usr/share/icons/ directory; prefix the extract command you end up using with sudo.
Also, I'd first recommend looking through the Arch / Manjaro repositories and see if the icon pack you want to install isn't already there. If it is, you'll be able to install it using pacman, the package manager used in Arch / Manjaro.
If it's not in the official repos, look through the user repos.
Most of that stuff from "Guides" that require you to go use Nautilus and put the stuff in root folders and such is un-neccessary.
Go into your Home Folder, press CTRL-H. it will unhide all of your hidden folders. create a few folders
Create a Folder called .themes and another folder called .icons
GTK+ themes will go into the .Themes folder, and of course icons stuff will go into .icons folder. Shell themes you can install straight from the GNOME tweak tool.