Visit
https://unity.com/Click Get Started /
https://store.unity.com/Go to Individual tab and select Get Started under Personal /
https://store.unity.com/download-nuoSelect First-time users if you are new, feel free to use Returning if you are already familiar and just need an update
Requires 9.6 GB of disk space
Install
Create Unity ID
Select Platformer Microgame
When Unity has finished downloading and installing click Launch Unity
Once everything has loaded and imported, there will be a popup in the center, click Start Tutorials
On the right side panel that has a highlighted and blinking border, follow the tutorial instructions and enjoy!