The AS5304 is a linear encoder. It can detect motion along a straight line. Is that what you're trying to do?
If instead you want to measure the angle of a rotating shaft, the AS5030 rotary magnetic encoder is what you need.
Whatever the case, the place to go is the
Kit of Parts page on the FIRST web site. You will find full documentation on each of the sensors provided in the Kit. The sensor you're asking about is in the
Parts Data Sheets section, as is the one it sounds like you need instead.