Are you looking for a link on how to download SQL Server 2019, well here it is
You can also download the whitepaper from here : https://info.microsoft.com/ww-landing-SQLDB-Microsoft-SQL-Server-WhitePaper.html
If you need help on installing SQL Server, then watch this course. It will show you how to set up SQl Server properly.
The Complate SQL Server DBA Bootcamp : Beginner To Expert