I converted mine (old ATX cube) to a bench supply. It was easy, and certainly doesn't require any tutorial.
I suspect that most supplies one finds nowadays (excluding 20-year-old ones from someone's basement) will be the same general design as mine. What this means is that you don't have to mess around with dummy loads to fool the PSU into thinking that something's connected. (Older PC power supplies wouldn't work unless there was a sufficient load connected to the +5 volt supply.) All you need to do is find the "power on" line and tie it to ground, and the thing will come to life.
Sorting out the wires in the motherboard connector can be a challenge. Some of the "instructable"-type pages on the web aren't totally accurate in this department. I found a good online resource with pin identifications, which I'll post later when I can retrieve it.
And as Ron said, if you have any specific problems or questions, folks here can answer them.