This i solved.
To have a client and server in UDP it´s very easy, though a bit dangerous, as you don´t know for sure if it´s working or not unless you test it (UDP just send and don´t care about anything else).
So basically to do it.
Client.Send(buffer,0,buffer.size,IPAdress,Port); byte[] rec = Client.Receive(ref IPAdress);
To receive you must have bind it to an IP, so you can just bind it to listen to Any ipadress, The port however needs to be set (i think), and you want to do that, as listening to everything there is, is not a good idea.
So ref IPAdress will be that listening IP and Port.
So it´s very easy to set up. And you can use the same UDPClient for both receiving and sending if you want, though it´s probably better to have 2 separate .