How to use a shared library generated from simulink model in visual studio?

Hi I generated a dll from my simulink model using ert_shrlib.tlc. I am calling this library in visual studio useing PInvoke. Now I don't know how to call functions (modelname_initialize, modelname_step) viewed in dependency walker software. I'm writting my code in visual studio express 2013 in C# language. Are there any tutorials on this subject? Thanks for your answers Best regards Jernej