Step 2: Put the Lime in the Coconut...
Measure out two quantities of hydrogen peroxide and pour it into your non-metalic container.
Measure out one quantity of hydrochloric acid and pour it in. ("Do like you oughta, add acid to water" to minimize the chance of an out-of-control exothermic reaction.)
Be careful with the acid. This stuff (at 10 molar) is strong. Mine fumed a bit when I took the cap off. Don't breathe it directly, and be sure you've opened the kitchen window.
The starter etchant you've just made, on the other hand, is not so bad -- around 3M HCl with a medium-strong oxidizer. I find it doesn't fume much at room temperature when I'm re-using a batch.
That said, you've got to be very careful to keep it away from metal -- especially your stainless-steel kitchen sink. It'll eat the stainless coating right off. Keep plenty of water flowing at all times when you've got any of this (even a drop) near the sink.