I'll second Oppi Untracht's book. Plenty of recipes for pickles, patinas and electrolytes for plating. All the techniques, all the tools are described. Metals, stones, chemicals and tools are often given with their names in English, French, German, Italian and Spanish; sometimes chelicals are given with their old names (can be useful when comparing with old books that call for "Muriatic Acid").
I used to play mainly with brass and nickel silver,as cheaper substitues for the expensive yellow and white metals.
If you can manage to saw, file, and bend nickel silver, then doing the same with sterling silver will be a doddle afterwards.
Doing cabochon setting practise with sterling silver and emeralds would be expensive, too. try the flat-based glass beads for table decoration, or for fish tanks, and nickel silver.
K.