If you are looking for documentation or guides ("helpful paper") to get started with this specific version:
: Use the Unity Personal license. It is free for individuals and small businesses making less than $100k/year. Unity 2018 for Mac Free Download
To download a legacy version like for Mac, you should use the official Unity Download Archive , which hosts all previous versions for free. ⬇️ Download & Installation Steps Visit the Archive : Go to the Unity Download Archive . If you are looking for documentation or guides