I apply a waxy coating to a polished copper plate and, with a rounded needle, draw through the coating.
Immersion in ferric chloride corrodes, or etches, the areas of exposed metal.*
I also use a drypoint technique (using a sharp tool).
Ready to print, I apply ink, and wipe it off the surface, while it fills the etched grooves.
On the press, fine paper is placed over the plate, with protective blankets on top, and all is squeezed (pulled) between heavy steel rollers.
As opposed to a low-cost photo-mechanical reproduction, like a so-called gicleé made by an ink-jet printer, an etching is an original print because each one is inked, wiped, and printed by hand. It has a characteristically tactile ink surface and plate impression.
* FeCl3+Cu+H2O=FeO+CuCl3+H2