The easiest way to get started with estats is to have a look at the examples in the Tutorial section.
For an applied example of estats please visit the NGSF project (https://cosmo-gitlab.phys.ethz.ch/cosmo_public/NGSF).
The following flowchart illustrates a possibility of how the different modules could be used to construct a pipeline used to constrain cosmological parameters based on a weak lensing survey catalog.