Simulating a zigbee wireless sensor network using omnet++

Question

Please how can I simulate a zigbee wireless sensor network in omnet++ with a total of 30 nodes. I'm new to omnet++. I'm using omnet 6 Below is my network file.

package projtest4.simulations;
import projtest4.ZigbCoordinator;
import projtest4.ZigbRouter;
import projtest4.ZigbEndDevice;
import projtest4.ZigbPhy;
import projtest4.ZigbMac;
import projtest4.ZigbNet;
import projtest4.ZigbApp;
network ZigbNetwork
{
 submodules:
 coordinator: ZigbCoordinator;
 router1: ZigbRouter {
 @display("p=127,64");
 }
 router2: ZigbRouter {
 @display("p=230,76");
 }
 endDevice1: ZigbEndDevice {
 @display("p=364,27");
 }
 endDevice2: ZigbEndDevice {
 @display("p=348,175");
 }
 phy: ZigbPhy {
 @display("p=318,206");
 }
 mac: ZigbMac {
 @display("p=371,256");
 }
 net: ZigbNet {
 @display("p=421,302");
 }
 app: ZigbApp {
 @display("p=460,359");
 }
 connections:
 coordinator.out --> router1.in;
 router1.out --> router2.in;
 router2.out --> endDevice1.in;
 router2.out --> endDevice2.in;
 mac.out --> phy.in;
 phy.out --> mac.in;
 net.out --> mac.in;
 mac.out --> net.in;
 app.out --> net.in;
 net.out --> app.in;
}`

I have defined the modules imported by myself. Below is an example of a module I created

simple ZigbMac
{
 parameters:
 @display("i=device/antenna");
 gates:
 input in;
 output out;
}

Please I also need to understand what to do here (error in omnrt++)

src/Makefile does not exist. Please use "make makefiles" to generate it!