Digital map using map of OpenStreemap

Question

Hi everyboy,I am doing a project using map of Openstreetmap.I loaded map very successflly.But I don't know show my position in map when I enter coordinate .Coordilate gets to xml file of Openstreetmap.I used on Ubuntu and very  successflly.But I convert to C# ,I don't  success. Have you ever do it?Can you help me?