The easiest way to create a Blazor project (assuming that you've kept your version of Visual Studio 2017 up-to-date) is to use File | New | Project, pick the ASP.NET Core Web Application project type, ...

Small businesses can leverage Visual Studio to create customized in-house applications that meet unique needs. Whether you’re building dynamic mobile apps or refining your web presence, this IDE ...

To create a Blazor-enabled version of the page (and to make as few changes as possible) all you need to do is wrap that method in another function and call that function from your Blazor code.