  We develop an $A_4 \times Z_4 \times Z_2$ symmetry extension of Standard
Model under the minimal extended seesaw (MES) mechanism which successfully
predicts neutrino masses and mixings patterns. This model breaks $\mu-\tau$
symmetry of neutrino mass matrix and explains leptonic mixing with non-zero
$\theta_{13}$. We study the phenomenological results of the keV-scale sterile
neutrino as a dark matter candidate along with other phenomenologies such as
neutrino oscillation observables, neutrinoless double beta decay, baryogenesis
via leptogenesis, etc. Dirac CP-violating phase $\delta_{CP}$ and two Majorana
phases $\alpha$ and $\beta$ are also calculated from the leptonic mixing
matrix. Best-fit values of the model parameters and neutrino observables are
calculated from $\chi^2$ analysis. The model predicts best-fit values of
neutrino mixing angles to be $\sin^2\theta_{23}=0.555,\
\sin^2\theta_{12}=0.301$ and $\sin^2\theta_{13}=0.022$ for normal hierarchy.
Significant results consistent with experimental data are also observed for
effective neutrino mass $m_{\beta\beta} \sim (0.97 - 5.02)$ meV, effective
electron mass $m_{\beta} \sim (0.084-0.41)$eV and sum of active neutrino masses
$\sum m_{i} < 0.12$ eV. The model does not favour Inverted hierarchy at the
3$\sigma$ level with the given parameter space.
