Options.txt needs the line;-
LCDName = ssd1306_128x64
and depending upon how you want the keyboard's pgup and pgdown keys to work;-
keyboardBrowseLCDScreen = 1
Splits lines connect
SDA to GPIO 2 pin 3
SCL to GPIO 3 pin 5
Non-split lines
SDA to GPIO 0 pin 27
SCL to GPIO 1 pin 28
Stephen White