|You don't usually get a user manual for a PSU. You install then, plug everything in, switch on it either works or it doesn't. |
If it doesn't work, as is obviously the case here, there are only a limited number of possibilities. Either you have not connected everything properly or there is something else wrong that has nothing to do with the power supply. This assumes of course that it is a properly functioning power supply to begin with.
The motherboard manual is most likely to be your best source of information as that will tell you where each of the connectors on the power supply is supposed to go.
Knowing what the problem was in the first place that prompted you to change the power supply would help.