Etching is a really fun technique, and can be used on lots of metals including copper and silver. There are a few steps, but its pretty easy to do.
Materials you need:
Press and Peel paper (blue)
metal (silver in this case)
acid (ferric nitrate for silver)
clear packing tape
saftey equiptment like gloves and goggles
pyrex bowl/pan, large enough for your piece
1. Prep your design
Designs need to be black and white- no gray, no color. This is important! Black areas (where toner will adhere to the paper) will be protected (un-etched) so pay attention to the positive and negative spaces in your design.
Writing will need to be reversed
Print onto the Press and Peel paper as per the manufacture's directions (use an old fashion copier, or a laser printer)
2. Clean your metal!
This step is so so so important. Don't skip it, and don't skimp. If your metal isn't clean, the transfer won't adhere and you will be disappointed.
Most directions state "clean your metal until water sheets off". Here's a video of what that means:
I like to use a brass brush, Dawn dish soap and and pumice powder to scrub it up. Using something course like a scotch bright pad or steel wool can help give your metal a "toothier" surface, which is easier for the transfer to stick to.
Set your iron to no steam, and at a medium heat. Make sure you have tweezers handy, as you metal is going to get hot. Iron over your pnp paper, and peel it off. Your design can be touched up with nail polish (use a color, not clear so you can see where it's been applied) or sharpie (doesn't work as well as nail polish).
Cover the back of your metal with a strip of packing tape, and drape the tape over your pan of acid, leaving your piece in for about 2-4 hours. Check it on the early side and see how deeply it's etched.
USE YOUR SAFETY GEAR!