How to install blazor template

i update my vs ide 2017 from itself. approx more than 7GB things download and install. i again check the version then it was showing VS IDE version 15.7.2 but found no .net core 2.1 version when try to open project and blazor template was missing.

from this link https://www.c-sharpcorner.com/article/asp-net-core-getting-started-with-blazor/

i came to know that i need to install Install .NET Core 2.1 Preview 2 SDK and i did.

again try to install https://marketplace.visualstudio.com/items?itemName=aspnet.blazor

when i try to install ASP.NET Core Blazor Language Services

then i encounter some problem. later i will post the error message.

please guide me what i need to open blazor project with my VS2017 v15.7.2.

thanks