How to use .net metrics for version 4.8

Question

I have custom strategies on ninja trader which is tied in to Net 4.8. How do i add telemetry info as the Microsoft site shows headlining for "applies to NET Framework 4.6.1 and later versions" https://learn.microsoft.com/en-us/dotnet/core/diagnostics/metrics-instrumentation

Tried to add the metric package at top but the compiler cannot detect it

using System;
using System.Diagnostics.Metrics;// cannot find the package                 
public class Program
{
    public static void Main()
    {
        Console.WriteLine("Hello World");
    }
}

see the fiddle targeting ver 4.8 Fiddle link