Cube autopilot + Here 3+ I2C board connections

Hello ,

i got a cube orange a here 3 +rtk and a tarot landing gear controller, am bit confused as to how those connect .

In the wiring ecosystem CubePilot | Autopilot-on-Module | Blue Manufactured in USA | Blue Assembled in USA | Pixhawk Original Team it shows that you connect a CAN bus splitter and put the HERE 3 there together with servos . It also shows you give it a 5.3V

In the package of cube pilot there was an I2C board (doesnt look you connect power to it), which i dont know what it is ? is this a replacement of the CAN Bus Splitter ?

I also want to connect Tarot X Electronic Landing Gear Controller TL8X002 .

Should i connect the here 3 to the CAN and the landing gear to the AUX ?
Do they need to be on a can bus splitter ?
What is the I2C board for ?

Thank you for your time,