FOSS gamedev and creative worlds

When I go to usr/share/minetest and go to the mods folder to try to extract a mod, it gives me a message along the lines of: Permission Denied. How do I get around this?

use your file manager as root

You should not touch Minetest's core game files to mod your game. You can add mods in ~/.minetest/mods/minetest/ (create the folders if needed).