In which store should I add the Client Authentication Certificate?

I'm developing a WCF webservice that is consumable only internally and it is online. I am using Certification Authentication and following this tutorial.

My question is that in Client Certificate authentication, where should I add the client certificate in the server?

I tried in Trusted Root Certification Authority store, but the service is returning

System.ServiceModel.Security.MessageSecurityException: The HTTP request was forbidden with client authentication scheme 'Anonymous'. ---> System.Net. WebException: The remote server returned an error: (403) Forbidden.