Zither and oud tuning?

I bought a zither and an oud (Arabic lute) at an estate sale. The zither is Russian, as evidenced by the Cyrillic writing on it. I know you need a special wrench or 'nut' to tune zithers, but how are they tuned? With my sketchy Russian, I was able to determine that the zither is in the key of 'G'. The oud is an eight string or 'course' instrument, but I can't find any books on it anywhere. How are they tuned? It appears to be an alto oud.