5v and gnd is certainly its power input.
if your motherboard doesn't have power for it, you need to get it through Molex. You can get +5v that way, mine uses a pass through adapter that outputs molex and the 2 pin power connector for the turbo switch. I'm not sure where to find those outside of the guts of an old machine, so i would just hack up your basic molex cable and connect +5v and gnd to the turbo display.
That display looks quite butchered though, as if somebody took an iron to it years ago. Id expect it says hi and lo if it works though 😀. I'd clean off that corrosion too.
Sup. I like computers. Are you a computer?