To use .NET Core 2.1 with Visual Studio, you'll need Visual Studio 2017 15.7 Preview 1 or newer. Make sure you've got the latest Visual Studio 2017 Preview.
Read the .NET Core 2.1 announcement post to find out what's new in .NET Core 2.1.
For Linux, we recommend installation using a package manager
After you've downloaded, enter to win a 24x36" poster of the CODE Magazine cover signed by .NET rock-stars Scott Guthrie, Scott Hanselman, Anders Hejlsberg and Scott Hunter. All entries are eligible for a free subscription to CODE Magazine! See contest rules and regulations.