Alot of servers have at least one built in video output head but if it’s an older device you might need to look for an HD15 VGA port… Some servers might have had some sort of micro port or proprietary port/dongle setup as well. Might refer to the documentation for the chassis/motherboard first… It’s possible you have what you need already.
Oh fantastic, sorry if I missed that detail in the original post. Thought you might have had an old eBay blade server or something. Hope you got it working!