Classic InSAR analyzes phase changes on the base of image pairs (e.g. A+B)
If you want to observe phase differences over a longer period, you can either compute more pairs (B+C, C+D, D+E…) or compute differences between multiple dates to one primary image (A+B, A+C, A+D,…).
An example on the combination of multiple images is given at the end of this tutorial: Sentinel-1 TOPS interferometry, but it only computes an average displacement over multiple image pairs.
Another example is given in this tutorial: https://eo-college.org/resource/insar_deformation/ (only the last part on multi-temporal analysis is valid, the rest is quite outdated from a technical perspective)
There are distinct methods on time-series analyses of displacements, but as you are new to InSAR I would not recommend rushing into these to quickly. Nevertheless, the collection on this topic is here: StaMPS - Detailled instructions