Portenta H7 Issue with I2C interface

I wanted to connect Portenta H7 with Raspberry Pi. I wanted to keep the portenta as a slave & RPi as a Master I figure out a lot but didn't get anything about what can I do to Connect the Portenta with RPi, And while trying the I2C interface between the RPi and Portenta I was facing problem in Register Address. I got the Device address(0x08 this is the Portenta Address) but unable to read/write the logic at that Pin because of the Register Address. Please help me to resolve this issue. Thank you in advance.