Apart from selecting "Enable coverage analysis", it is needed to specify one out of: Entire System, Referenced Models, Subsystems. From documentation see that:
Entire System (default): Coverage data is collected for the top-level model, as well as all supported subsystems and model references.
Referenced Models: Coverage data is collected for one or more referenced models. To specify the referenced models, use the parameter Select Models. You can also specify the top-level model itself. Subsystem: Coverage data is collected for a specific subsystem. To specify a subsystem, use the parameter Select Subsystem.
You then run the model, and then should see a Coverage tab as part of the toolstrip, where you can get access to a report of the coverage details, generate a report, highlight coverage on the model.
Hope it helps!