Now that I own four B5092 and one B5094 Nixies I have to turn them on. Datasheet (a scan of) can be found on Internet, together with a wealth of information on these displays. Anyway, as I understand it, it is pretty simple: 170 Vdc and a series resistor (10k in case of B5092) on the anode. The current is less than 3 mA per filament switched on.
Either use a stack of batteries or a DC-DC upconverter. Plenty of projects online for DC-DC step-up converters. But ... I have also found a kit from Slovakia for less than 12€, designed just for Nixies and alike.
In four days it came to my door, even with a real stamp on the envelope! Yes, I used to collect stamps. Top quality PCB and components. Clear instructions in real English language. Assembly should take less than an hour to everyone.
So far I am a satisfied customer of www.lumos.sk kit.