C# / Dotnet importing classes syntax

does someone know if this way of import classes in C# is correct?
[Code example of importing]

Btw my issue was "Ambiguous reference", I resolved with this

using PathString = Microsoft.Owin.PathString;

            OAuthOptions = new OAuthAuthorizationServerOptions
            {
                TokenEndpointPath = new PathString("/token"),
                Provider = new OAuthAppProvider(),
                AccessTokenExpireTimeSpan = TimeSpan.FromDays(2),
                AllowInsecureHttp = true
            };

>Solution :

Common practice is to have a using statement at the top of your class, in your case

using Microsoft.Owin;
public MyClass
{
    public void someMethod()
    {
        var endPointString = new PathString("/token");
    }
}

In cases, when you have multiple namespace having same class name, then we use full namespace to access the class.