ICM45686 - How to set up external sensors in FIFO

Hi,
I'm interested in using ICM45686 with a magnetometer attached to the AUX interface and I want to be able to access this data inside the FIFO. However, whatever I tried, I couldn't get this to happen. I can get I2CM communication going with the mag, read from it and write values to its registers, but I can't get the data it would return into FIFO. Any pointers?