ITO is a clear, conductive liquid/film and in ITO (Indium Tin Oxide) Coated Glass it is used as a coating on a 1mm glass sheet. This is a very interesting material, also used in scientific research and LCD/OLED manufacturing.
One side of ITO (Indium Tin Oxide) Coated Glass is coated in ITO, you can use the flat of a blade or similar to scrape away some of the film to create 'traces' - just be careful because as it is glass, any nick-lines will cause it to break on the line (that's how a glass cutter works) It may also be possible to use a laser cutter to pattern it.
It's not possible to solder to this material, but you can use conductive inks, paints, copper tape (with conductive adhesive) and alligator clips to make contact.
Adafruit Product Page: https://www.adafruit.com/products/1310