Explanation of each data received

Is there any guidance or explanation for every type of data received here? For example, what does the x_rms_ACC_G means?

These terms are self explanatory.
for example x_rms_ACC_G == rms acceleration in x-axis measured in g
the detailed in fo can be found in the product manual as well.

may I know where can I find the product manual?

on the product page under resources