It depends on the system and host disk controller. You will need to provide additional information about your system to gain specific assistance. You can also go to the website for your system and host disk controller to gain access to documentation about this process.
Buy one, find power, space and cooling for it. Attach the network cable. Configure it. Allocate storage to the hosts that need it.
To go beyond that, we need to get some more details about what it is that you have, and what you are trying to achieve.