View the console and issues with xcode

Hi,
So I have entered my file (main.m), and I am able to successfully modify it, however, after Pressing "cmd + r", (the program runs successfully, but I don't know where the output is.
In addition, if I make a deliberate Mistake, I am told that the "build failed", but I am not told where The issue was.
A final question, how would I create a "main.h" file and quickly navigate to it?
Thanks