Use Canvas2 of the XCS file.  Using the P2, cut out the base and the four little support risers.  Glue the cut edge of the support risers to the bottom of the base piece, aligning them to the edges of the base piece.  In attached photo it's obvious I am reusing a scrap, that's what we all do.  In my case, this added a little problem, because this scrap is badly warped.  So when I put it in my F1 I had to use some tape to hold it flat.

I used some cheap clear plastic ball markers from Walmart for this project.  I liked the bright colors, and they are transparent, which makes things come out better.  As seen in the second picture, the risers hold the base up a little bit, to compensate for the length of the pins in the back of the markers.

Adjust focus of F1, use Canvas 1.  I left an example image (anonymized) with settings that worked really well on the orange and the pink markers, but you should probably reduce the power a bit for the green markers.

Notice you're using an inverted bitmap image, as the engraving will make the plastic rougher, making it look white/gray.

After engraving the picture on the markers, flip them over and color over them on the back with a black Sharpie.  this is so any part of the inverted that is white (what you want to see as black) sees the black background of the Sharpie ink (because the markers are transparent).  You could use spray paint or black electrical tape too.