Tom:
There are automatic flash functions built into this flash.
IIRC, it is similar to the 45CL1 flash so the manual linked to in Ben's post above has the answers to your questions (although they may not be obvious or as clear as they might be).
First, you need to download either Ben's manual, or this one, which is the full, multi-language version:
http://www.metz.de/fileadmin/fm-dam/Download/Photo_Electronic/Bedienungsanleitung/mecablitz/mecablitz_40_bis_45/mecablitz_45_CL_1_NC_D_F_NL_GB_I_E.pdf
In the case of the multi-language version, the equipment photographs you are interested in are on or near page 57 (and are much clearer). The english instructions start on page 29.
If you look at the photo on page 57 of that manual, you will see a dial in the centre that has an indicator on the bottom which can be set against the appropriate film iso. The other end of that indicator rests against a series of f/stops. Those f/stops are adjacent to a rotating dial with a series of distances printed on it. Along the top of that dial are 5 short lines under the word "AUTOMATIC".
If you set the point of the triangle against one of those lines, you will have chosen one of the 5 automatic ranges available. The triangle will be adjacent to both a distance and an f/stop. The f/stop is the one you set on your camera, and the distance is the maximum flash to subject distance that you can use with the flash.
You may notice that there are two further indicators on the dials - a "W" and an "N". If you use a wide angle diffuser on the flash, the "W" indicates the revised maximum flash to subject distance.
As to the shutter speed for the Contax, use the maximum speed that the camera's focal plane shutter synchs flash at. As I understand it, that is 1/125 second, but you should check that.
Hope this helps!
Matt