  The next$-$to$-$minimal supersymmetric standard model (NMSSM) featuring
constrained mSUGRA model, has the capability to inherently anticipate a light
dark matter component within the existing limitations encompassing Higgs data,
sparticle$-$mass constraints, dark matter exploration, muon g-2. We examine
neutralino dark matter within the NMSSM framework by conducting a comprehensive
analysis of its parameter space. This involves evaluating neutralino capture
and annihilation rates within the Sun. The exploration of potential detection
strategies for neutralino dark matter in neutrino experiments hinges on the
composition of neutralinos and their primary annihilation pathways. Our study
also involves reassessing the maximum thresholds for branching ratios of lepton
flavour violation decays $BR(\mu\rightarrow e+\gamma)$, $BR(\tau\rightarrow
e+\gamma)$ by directly referencing the constrained limits on $ \Delta a_{\mu} $
from $ g_{\mu}-2 $ experiment. This work also presents constraints of muon
flux, photon, positron and antiproton flux, specifically its independence from
experimental intricacies and the universal applicability of recalculation
coefficients across NMSSM model. Within the scope of this research, we have
chosen to utilize this NMSSM scenario as a case study to investigate the
funnel$-$ annihilation mechanisms pertaining to light dark matter and the
concealed Higgs decay. In this particular scenario, our findings reveal that
there exist decay channel$-$annihilation mechanisms for the lightest
supersymmetric particle $ \tilde{\chi_{1}^{0}} $, which include the $h_{2},
h_{1}, Z, W^{+}, W^{-}, G, s, S, b, B, c, C, a, A, d, D, l, L $ decay funnels.
