Video 1. Fabry Perot Interferometer by JFC UCL (2016) Source. Description only, reasonable animations. Considers the case of two nearby beam splitters.
Video 2. Fabry-Perot Introduction by Williams College Physics (2020) Source.
Shows a working device. Confocal optical cavity, one of the mirrors scans back and forward moved by a piezoelectric motor, this is called a "scanning Fabry-Perot interferometer".
Does not produce an interference pattern, only an on/off blob, which is then fed into an oscilloscope for analysis. The oscilloscope shows both the mirror displacement (which is given by a voltage) and the light detector output.
Video 3. Aligning a Scanning Fabry-Perot Interferometer by University of South Florida (2016) Source. Very detailed, and shows of some nice equipment and techniques.