I2C-1 communicate with tca6416 i2c port expander

hello,

i'm using the beaglebone Rev A3 (AM335x processor) with arago image
(not angstrom image), how do i use the I2C-1 module to communicate
with TCA6416 i2c port expander ? i'm a beginner, how i start to write
a I2C code using c programming in ubuntu?