How do I interpret the read values from accelerometer and gyroscope registers?

You can see the terms LSB/dps and LSB/g relatively in our datasheet Gyroscope Specifications and Accelerometer Specifications sections. You need to look at your Full-Scale Range setting for accelerometer and gyroscope, then find the corresponding sensitivity scale factor values from table. Those sensitivity scale factors used for converting from LSB to dps (degrees per second) and g units.

When your accelerometer full-scale range is set to ±2g, you will read 16384 LSB as 1g from the accelerometer output, hence you can make your conversions based on that. When your gyroscope full-scale range is set to ±250 dps, every 131 LSB will equate to 1dps.