I recommend you read everything but I will underline the key points
The compass sensor works very much like a normal compass. This is both a good and a bad thing. The good side to it is the compass has been around for a very long time and has been proven accurate, that is when it is not being acted upon by an outside force other than the earth’s magnetic pull. The bad side is you want to put this on a robot that runs on electricity and it moves around.
