This is identical to the instructions available from the Official Documentation:

A shorter and automated install is detailed in the later section but for now,

Long Install Method:

Setup your computer to accept software from packages.ros.org.

sudo sh -c 'echo "deb http://packages.ros.org/ros/ubuntu $(lsb_release -sc) main" > /etc/apt/sources.list.d/ros-latest.list'

Setup your keys

sudo apt install curl # if you haven't already installed curl
curl -s https://raw.githubusercontent.com/ros/rosdistro/master/ros.asc | sudo apt-key add -

Installation

sudo apt update
sudo apt install ros-noetic-desktop-full python3-rosdep -y

Environment Setup

echo "source /opt/ros/noetic/setup.bash" >> ~/.bashrc
source ~/.bashrc

Initialize Rosdep

sudo rosdep init
rosdep update

Short Install Method:

Install

wget -c https://raw.githubusercontent.com/qboticslabs/ros_install_noetic/master/ros_install_noetic.sh && chmod +x ./ros_install_noetic.sh && ./ros_install_noetic.sh

Uninstall

wget -c https://raw.githubusercontent.com/qboticslabs/ros_install_noetic/master/ros_uninstall_noetic.sh && chmod +x ./ros_uninstall_noetic.sh && ./ros_uninstall_noetic.sh