I would first do a fft (link) of your signal to determine what part of the spectrum are your valid signals, and what are noise. Then use the Signal Processing Toolbox designfilt function to design a Chebychev Type II bandpass filter to filter out the noise and the d-c offset and low-frequency baseline drift.
Then use the cumtrapz function once with your acceleration signal to find the velocity, and use it to integrate the velocity signal to find displacement.
