So, in a standard Nengo Ensemble, the neurons are not connected to each other unless you add a separate recurrent connection, i.e.
ens = nengo.Ensemble(n_n> eurons=10, dimensions=1)
nengo.Connection(ens, ens)
In an EnsembleArray, what happens is if you have a 10 dimensional input signal, and each Ensemble in the array is 1D, then 10 Ensembles get created. The 10 dimensional input signal is broken up to send a single dimension to each Ensemble and then the output of the Ensembles is combined on the output side so that you don’t need to make 10 separate connections to access the EnsembleArray output. It’s all in one place. There’s also some discussion of this in this thread: High-dimensional `Ensembles` vs. many low-dimensional `Ensembles`
Does that help?