so i now i only know how to begin a baud rate, how about the port?
I don't understand the question, I guess. A PC can have multiple devices connected to it, and each connection creates a new real or virtual COM port. The code running on the PC needs to connect, then, to the correct port.
The Arduino has only one real, and no virtual, serial port. So, there is no need to "define the port". It simply is.