在。net web应用程序中实现XML请求

I have been reading and reading but I just get more confused the further I go. I am building an ASP.NET 4.0 web application in C#. I am trying to implement credit card processing. The company I am using has supplied an example XML SOAP request and response but I am not sure what to do with that. I am a novice developer and am new to all of this. I just don't even know where to begin. Any help is greatly appreciated, I also have to send over SSL but that is probably a whole other question. I have been reading and reading but I just get