BMX160: How to write or read a register?

I have BMX160 DOF sensor and I want to write or read data into/from a specific register.

I want to activate FOC function and read number of steps from step counter.

From datasheet, FOC resgister is 0x69 and step counter are 0x78-0x79.

how I can activate FOC and read step numbers from step counter?

I can make a simple codes and partially understand libraries. So, in this case, I never, ever understand how to do.

Please help me.