I have a few videos I have come across that talk about converting a server power supply for other uses. I’m including them here.  

BONUS: A page about the HP DPS-600PB Power supply.

BONUS 2: A page about converting other power supplies. 

BONUS 3: Page on converting a power supply on ArcadeEd’s page: https://arcaded.discussion.community/post/server-power-supply-mod-8171641

 

HP DPS-600PB Power Supply – DPS 600 based:

 

HP DPS460BB Power Supply DPS 460 based:

Another HP Server power supply:

https://youtu.be/iB4cMkyzYpI 
These should get you started.  Dell has a similar setup.  These are some good videos to get you started, with a few links to learn a bit more about converting power supplies.