Sending pdf attachment (SOAP) Web Service by C#

Question

Hello,
I'm beginner and trying to write a Web service for my coursework, but I'm very embarrassed. I don't know C# even.I have to write a WebService which implement sending a pdf file (SOAP attachment) from client side to webservice side on C#. Can somebody help me, with some decision. I'm really very bad on this field and I need some code which I only have to Copy and Paste. I tried to do something but it was unsuccessful. I will be happy if someone can help me.
Best Regards
Hristo Alexiev