Sorry to be confusing. No there is no front and back. @deirdrebeth explains it better than me! . Once you have your artwork ready; i.e invert the colors so that the white is black and the black is white - or rather clear. Then reverse that image and engrave on clear acrylic. Turn over the acrylic so the “back” is now the “front.” i.e the engraving is facing away from you. Then place a black piece of acrylic behind it and the engraving really pops out.
I did this with blue on this nativity.
and with black on this one - which has another spacer as well in between:
Look for “no fog” super glue - or search the forum for acrylic weld.
For display For display you have a few options. If you attach another layer - either a clear or colored acrylic frame - 3 layers will stand up by themselves. Can even make a wooden frame for the front with date, and other particulars. Alternatively you can make a double base for it that the two layers slot into.