  We make a systematic calculation of the spectra and hadronic decays of the
$D_s$ system in a coupled channel framework, where the unquenched effects are
induced by the $^3P_0$ model. In the calculation, the wave functions are
obtained by using a nonrelativistic potential model and are handled precisely
with Gaussian Expansion Method. Even though the fitting mainly focuses on the
spectrum, our model agrees well with the experiments on both the spectra and
the hadronic decays, suggesting that the coupled channel effect could result in
a reasonable and coherent description of the $D_s$ mesons. Based on the
calculation, we give a detailed analysis on various aspects of the excited
states, especially $D_s(2317), D_s(2460), D_s(2536), D_s(2860), D_s(3040)$. We
also predict that $D_s(2{}^3P_0)$ should be a $D^*K^*$ dominant molecule with
mass $2894$~MeV, which is only $5$~MeV below the $D^*K^*$ threshold.
