  The goal of this article is two fold. Firstly, we explore the dynamics of a
semigroup of polynomial automorphisms of $\mathbb{C}^2$, generated by a finite
collection of H\'enon maps. In particular, we construct the positive and
negative dynamical Green's functions $G_{\mathscr{G}}^\pm$ and the
corresponding dynamical Green's currents $\mu_{\mathscr{G}}^\pm$ for a
semigroup $\mathcal{S}$, generated by a collection ${\mathscr{G}}.$ Using them,
we show that the positive (or negative) Julia set of the semigroup
$\mathcal{S}$, i.e., $\mathcal{J}_{\mathcal{S}}^+$ (or
$\mathcal{J}_{\mathcal{S}}^-$) is equal to the closure of the union of
individual positive (or negative) Julia sets of the maps, in the semigroup
$\mathcal{S}$. Furthermore, we prove that $\mu_{\mathscr{G}}^+$ is supported on
the whole of $\mathcal{J}_{\mathcal{S}}^+$ and is also the unique positive
closed $(1,1)$-current supported on $\mathcal{J}_{\mathcal{S}}^+$, satisfying a
semi-invariance relation that depends on the generating set ${\mathscr{G}}$.
  Secondly, we study the dynamics of a non-autonomous sequence of H\'{e}non
maps, say $\{h_k\}$, contained in the semigroup $\mathcal{S}$. Similarly, as
above, here too, we construct the non-autonomous dynamical positive and
negative Green's function and the corresponding dynamical Green's currents.
Further, we use the properties of Green's function to conclude that the
non-autonomous attracting basin of any such sequence $\{h_k\}$, sharing a
common attracting fixed point, is biholomorphic to $\mathbb{C}^2.$

Complex Variables;Dynamical Systems