The documentation for that sensor is linked on the web site, and you should study it carefully.
To get azimuth requires that the magnetometer be calibrated in its final resting place. The best calibration overview and tutorial is this one: Tutorial: How to calibrate a compass (and accelerometer) with Arduino | Underwater Arduino Data Loggers
Tilt can be measured on two axes using the accelerometer, which for highest accuracy must also be calibrated. See this tutorial: How_to_Use_a_Three-Axis_Accelerometer_for_Tilt_Sensing-DFRobot