How to use Vivitar auto thyristor 283?

I have a Vivitar auto thyristor 283 and I put batteries in it but I'm completely clueless and new to flashes. I have a nikon film and a kodak digital will it work with these? It was given to me so I don't have a manual and I have no idea how to use it. And I have no idea what the dial on the side of the flash is telling me or how to set the sensor. Any help would be greatly appreciated!

I'll plus one on "BigAl" but insert a bit of a warning. Early examples of the 283 had a very high trigger voltage, no problem for the cameras of that era, but it can absolutely FRY the shutter in some newer cameras! There are any number of sites that will tell you how to test for the Good, the Bad and the Ugly 283's but the only really safe way to use them on camera is to test the actual voltage across the flash contacts with a good multimeter. Get the local science geek to help with this. That said, it's probably safe with most Nikon film cameras, the camera flash contacts are more robust than most brands, but test first.

It is also possible to use the flash off camera with a slave, Vivitar actually makes a pretty good slave with a tripod mount on the bottom and a hot shoe for the flash, but it will not work with digital cameras that employ pre-flash unless you disable the preflash. Wein (and others) make "digital" slaves that will supposedly work but from what I've seen results can vary.

I could have saves a lot of typing! The manual is at:-
http://www.butkus.org/chinon/vivitar_flashes/vivitar_flash_units.htm
just scroll doen to the 283
The problems with trigger voltage are not referred to because it wasn't a problem when these were introduced.

Firstly does it warm up with batteries in? The switch is at the bortom of the back. The light next to the switch should glow when it is ready to go. The light is itself a switch - pressing it will fire the flash. Don't be looking into it when you do this! It should be OK on the film camera but don't try it on the digital. The trigger voltage on these can be high enough to fry a digital camera's electronics.
Does your Kodak actually have a flash connection, either via hot-shoe or PC socket? Most just have a built-in small flash. If this is the case then you could trigger the Vivitar by arttaching an optical slave trigger to it. These fire the flash when another flash (ie the one in your Kodak) goes off nearby. Because there's no physical connection the voltage is not a problem. You would have to stop your Kodak firing off it's flash 2 or 3 times per shot like many do to prevent red-eye. TYou want it to fire once only!
Now, to the flash itself. Your sensor should say 'Auto Thyristor' on it. I say this because there are also 'VariPower' fittings - it does pull out but more about that later. On the sensor the knurled ring turns with the window on the right side showing four colours or 'M'. These colours are matched by coloured slices on the dial on the side.
This dial is a calculator. At the bottom you will see DIN/ASA film speed settings. By gripping the flash firmly (both hands is best) you can turn the dial so the needed film speed is under the little black arrow. Diametrically above the arrow are the four colour slices with a colourless slice in the centre. These slices are marked with a distance in feet & metres. These distances correspond to aperture settings at the very top of the dial. So with the ASA/DIN arrow on 21 DIN (that's 100ASA) the colourless slice (20ft) shows f5.6 with the pink showing f11.
You make sure the camera's aperture is set to that shown on the flash. Once you have the hang of it you'll be able to calculate variations to suit different circumstances but keep it simple for now.
All the distance settings assume the flash is pointing at the subject. If you are bouncing the flash of ceilings or walls then allow for the extra distance by setting a bigger aperture - that would be (say) f8 instead of f11 or even f5.6 instead of f11.
The sensor comes out because it can be plugged into a remote sensor cord with the other end of the cord plugged into the flash unit. This allows the flash to be a distance away from the camera but it's intensity is measured from the camera position. The camera end attaches to the camera hot-shoe if there's one so the voltage considerations need to be observed. You could just as easily plug a shoe'd slave trigger onto that end and then fit it to the camera.
Good luck - these are GREAT guns, Vivitar dropped them years ago but had to bring them back through public demand.