Blazor uses only the latest web standards. No plugins or transpilation needed. It runs in the browser on a real .NET runtime (Mono) implemented in WebAssembly that executes normal .NET assemblies. It works in older browsers too by falling back to an asm.js based .NET runtime.
If you want to get your hands dirty – Prerequisite:
Install the .NET Core 2.1 Preview 2 SDK (https://www.microsoft.com/net/download/dotnet-core/sdk-2.1.300-preview2)
Install the latest preview of Visual Studio 2017 (15.7 Preview 2.0) with the ASP.NET and web development workload (https://www.visualstudio.com/vs/preview/)
Note: You can install Visual Studio previews side-by-side with an existing Visual Studio installation without impacting your existing development environment.
Install the ASP.NET Core Blazor Language Services extension from the Visual Studio Marketplace. (https://marketplace.visualstudio.com/items?itemName=aspnet.blazor)