Being a knife maker and jeweller (both as hobby only admittedly) I
am fairly familiar with the stuff.
Also, I have made a damascus ring myself...
So long as it is annealed, regular saw blades will work just fine.
Remember to anneal by heating to non-magnetic then cooling as slowly
as possible - ie maybe in a bucket of ash.
I use steel files on ANNEALED steel all the time - it is fine and
often what they were designed for in the first place. However, if
you don't want to anneal it for whatever reason (I can't think why)
then you would need to use abrasives.
As for etchant, this is something that will get you dozens of
The simplest one is warm vinegar. Another is ferric chloride.
There are heaps of different opinions on this and as steel is pretty
easy to etch, most stuff will work. If you are really keen, try
looking up Damascus etchant on http://www.bladeforums.com/