Its so easy.
You open a cmd and write ipconfig.Thats your inside IP.Use this ip in your NAPT menu of your router/modem to open the slots.Open the slots for both TCP and UDP.Use the same slots in the DC++ menu in active mode.Go to http://www.whatismyipaddress.com to see you outside IP.Enter this Ip in DC++.If you use a firewall,open this ports in the firewall also.Thats it.