First thing is to check that the flash is suitable to use with your digital camera and check out at http://www.botzilla.com/photo/strobeVolts.html

I have a print out and it says that the 380EX and it fellows are all less than 6v trigger voltage so will not fry your camera's brain. Canon info and verified.

If you do not get any info you can still use it on manual by working the way it was done when flash first came available. You may get the information off a control dial on the unit [I do not know the unit from Adam] but have three other flash units which all have some sort of exposure dial.

The info is a Guide Number for use with 100 ISO film/sensor. If you set the dial to 100 ISO and look for 10ft or 3metres and see what f/ number it tells you to use. Many are f/5.6 or f/8, just could be f/11.

You multiply that number by ten and that is your guide number. f/5.6 is 56 f/8 is 80 etc.

To take a shot you find the flash to subject distance in feet and divide it into your GN. So long as the camera shutter speed is at sync or slower it has no effect on the exposure [unless there is ambient light worth talking about]. The aperture controls the exposure for you dependant on distance.

Some flash also have automatic settings and the dial shows you a distance and an aperture. If you work at that distance or closer the flash will sense the reflected light and adjust itself at closer distances.

Here the dial is set at 100 ISO and from the 10ft mark you can see it has a guide number of 56. The blue arrow and line indicates if I set the lens to f/5.6 I can work between 10ft and 18" likewise the red line tells me to use f/8 and I can work between 8ft and 18". For sync-sunlight work I would set the ISO to 200 and pick a shutter speed to match the.say f/5.6 at ten feet.

Except being a DSLR you are limited in getting the right [sync] shutter speed ..I was going to suggest 1/250.

[EDIT] with modern DSLRs you have a mode where the flash pulses or strobes to cover the 1/200 period that the shutter takes to traverse the sensor area while giving you an exposure value of up to 1/500 for any part of the sensor. The second blind starts to cover the sensor before the first blind has completed it traverse of the sensor with shutter speed faster than what used to be known as the 'sync speed'.

So you leave the ISO alone and close the aperture to f/8 [one stop less than the 'correct' exposure for the distance] and this permits a shutter 1/125 which I hope is a sync speed on your camera. If you want a more subtle fill you could try f/11 at 1/60 ... hope you see what I'm doing.

For more complicated things like TTL metering and camera control of the flash you need the manual but the above will get you started. If you do not have a dial but you are using digital so I suggest you start with the lens at f/5.6 1/125 and a person at ten feet in a normal room. If you over-expose you know the flash is more powerful so you try f/8 and f/11 etc. Bearing in mind you will need to give more exposure when you do not have a room around you to reflect light back onto the subject.

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If you shoot at 1/125 and you only get half the picture lit then you know your sync shutter speed is perhaps 1/60th ... but I think I read about your camera syncing at up to 1/250 ... but that is easy to check.

Hope this is not baby talk to you and that it helps to get you going

The modern flashgun has a hotshoe mounting which connects to the camera's firing system. The older flash guns designed for film cameras with 'sync plug holes' came with cables and little plugs to suit.

If you are not sure about the safety of the flashgun's trigger voltage or if it simply doesn't connect to the camera it is possible in some cases to use the camera's built-in flash gun to trigger external flash units with a 'slave trigger'. It may also be possible to shield the camera flash from the subject yet still trigger the external flash unit. There is a possible snag to this that some cameras emit a pre-flash which triggers the external flash before the exposure is made. This is not 'Red Eye' but a focusing feature.