The drawing on page #3 clearly shows the pin numbers. Pin #8 is physically near the "wedge end" i.e. on the left.
Only you can see where the backlight A,K terminal are physically placed.
The drawing shows A, K nearest to pin 8 (C1-)
RST pin is marked #1 on page 3.
I suggest that you follow the wiring diagram on page 5.
Use a series resistor in the backlight circuit. Since the display is Transreflective you do not need the backlight.
I have never used this display. Newhaven generally have example code. This normally "works" but is a bit crap.
The datasheet says the 8-bit I2C address (0x78) on page 7. But the diagram shows 8-bit (0x7C)
If you are using Arduino Wire.h library, the 7-bit I2C address is 0x3C (0x78)
Assuming that their 8051 code works, it is easy to convert to Arduino Wire.h
David.