Install

First, we have to check our environment has node, npm and create-react-app tools available.
Type

node -v

in command prompt/terminal to check node is available. If not available grab it from https://nodejs.org/en/. Just need to install it. Nothing else.
Then, check npm is available with

npm -v

If it is not latest (5.2+) or broken type

[sudo] npm install npm -g

Hit enter and check npm available.
To install create react app type

[sudo] npm install -g create-react-app

All prerequisite installed.
Then, go to the desired directory in terminal and type

npx create-react-app new-react

Change directory to this new-app. Lastly, start this brand new react application with

cd new-app && npm start