Hi PingMe,
what do you mean by:
"to sign on other router mikrotik with nat and those things? "
if your question is how to access the RouterOS server using telnet, the answer is, using windows command prompt (or run), write:
where ip-address is the RouterOS IP address. (it is the public IP address if you are accessing it from outside the network)
But, if you are asking about how to configure the RouterOS using telnet , you have read the manual on the following link:
http://www.mikrotik.com/testdocs/ros/2.9/
That can help you to configure the router the way you want.
Regards,
Alaa