"m" is the global associative array in Brightscript. If you wanted to use the same message port for your whole channel you would name it "m.port", and then it will work in all of your functions. If you just name it "port" it will go out of scope when the function it's assigned in closes.
You didn't actually say what your problem is, if you have one. I would suggest reading this board on threads concerning port usage. A lot of it won't make sense at first but there is literally no other way to get a handle on it short of having it explained in person or the answers you will get to specific questions here.
