How to use truststore and keystore to store certtifiactes in C# to establish a SSL secure connection to a SOAP service

Question

My client has given three crt files by a third party and they asked to send this as my web request truststore along with my certificate as Keystore. But I don't find any such concept of Keystore and Truststore in C#.

What I need to achieve is the SOAP request with Keystore and Truststore in c#