Box 1:

Box 2:

Box 3:

Box 4:

Note:
Example:
ProjectInfo testProject = isserver.Catalogs["SSISDB"].Folders["TEST"].Projects["Integration Services Project2"];
PackageInfo testPackage = testProject.Packages["Package.dtsx"];
Full example:
class Program
{
static void Main(string[] args)
{
SqlConnection conn = new SqlConnection("Data Source=localhost;Initial Catalog=SSISDB;Integrated
Security=SSPI;");
IntegrationServices isserver = new IntegrationServices(conn);
ProjectInfo testProject = isserver.Catalogs["SSISDB"].Folders["TEST"].Projects["Integration Services Project2"];
PackageInfo testPackage = testProject.Packages["Package.dtsx"];
testProject.Parameters["ProjectTestParam1"].Set(ParameterInfo.ParameterValueType.Referenced, "661");
testPackage.Parameters["PackageTestParam1"].Set(ParameterInfo.ParameterValueType.Referenced, "662");
testPackage.Execute(false, null);
}
}
}