Arduino Leonardo interfacing with PCA9555 I/O Expander

Hi all I want to interface Arduino with I/O expander and I want to control and regulate the pins of PCA9555 i/O expander so that I could blink some led's connected to I/O pins of PCA9555,
and also want to control the pins whichever i want to use

I have gone through I2c protocol it requires the device address of the PCA9555,
which is acting as Slave
so according to datasheet of PCA9555 there is some thing command Byte needed to be sent just after the address byte
as in my circuit A0,A1,A2 pins are connected to 5volt.

like first i do Wire.begin()
with device address and Wire.beginTransmission()
Now how should I write the settings for the Configuration Register in PCA9555
As this is the register which is responsible for I/O feature

$) :grin: :disappointed_relieved: :expressionless: :open_mouth:

The sparkfun site has some example code for a similar(?) chip - SparkFun I2C Expander Breakout - PCF8575 - BOB-08130 - SparkFun Electronics -

There is an important note here - PCA9555 data sheet, product information and support | -

The ic is of NXP Pca9555 ic