This is pretty useless article, because: >But how did he do it? Well, we can't give too much away The main reason I read the article was that I wanted to know how those flights were so cheap, but it appears to be a secret other than from vague explanation of "be flexible".
It's human optimization. Experts know the system in and out and can take advantage of almost free seats in flights. Don't bother, you don't have access to those seats through the regular booking system.