You can wire up the 4 remaining pins as follows. the one on the very left (Y- orange) can connect to digital 9, the next one over (X- green) connects to Analog 2, The next one over (Y+ blue) connects to Analog 3 and the last one (X+ gray) connects to digital 8. The X- and Y+ pins pretty much have to connect to those analog pins (or to analog 4/5) but Y-/X+ can connect to any digital or analog pins.
Search for the Adafruit TouchScreen library and install it
We also have a great tutorial on Arduino library installation at: