Web Api - multiple actions?

Question

I have those methods, using webapi:

//Responsible for getting or updating a template and it's shifts
public class AdminTemplateDefinitionController : AdminApiController
{
    public HttpResponseMessage Get()
    {
    }

    public HttpResponseMessage Get(int Id)
    {

    }

    public HttpResponseMessage Post([FromBody]ENTemplateDefinitions EnTemplateDefinitions)//add shifts to template 
    {
    }

    public HttpResponseMessage Put([FromBody]ENTemplateDefinitions EnTemplateDefinitions)  //   add skills to template.
    {
    }

    public HttpResponseMessage Delete(ENSkillInTemplate EnSkillInTemplate)// remove skiilId from template
    {
    }
}

For some reason I get this error: Multiple actions were found that match the request.

My RouteConfig is:

public static void RegisterRoutes(RouteCollection routes)
{
    routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

    routes.MapRoute(
        name: "Default",
        url: "{controller}/{action}/{id}",
        defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }
    );          
}

Any idea ?