Share 'How do I get started?'

Hello, Been searching the Blog and Forum here trying to looking for some basic step to get start build app with Ning API. I have signed up a Pro plan (now is in trail mode) and also I have a client who are opening access for us to develop things upon. I wonder what are the steps to get the necessary credentials so to make our first Hello World app? The links in this Blog post are broken: http:/…