Step 01 Download Key
Download the repo key to make sure everything is legit and secure.
Step 02 Add Yarn Repo to Ubuntu
Add Yarn Repo to Ubuntu
After adding Yarn's repo key add the repo to allow installation.
Step 03 Install Yarn without Node
Install Yarn without Node
Install Yarn without installing the recommended software, just in case you want to use something like NVM (Node Version Manager) to maintain an installation of node easily.