  We followed step by step the transition from an antiferromagnetic (AF) Mott
insulator to a superconducting (SC) metal in the
Bi$_2$Sr$_2$CaCu$_{2}$O$_{8+\delta}$ (Bi-2212) cuprate using the electronic
Raman scattering spectroscopy. This was achieved by tracking the doping
dependence of the spin singlet excitation originate from the AF Mott insulator,
the normal state quasiparticles excitation related to the mobile charge
carriers and the Bogoliubov quasiparticles related to the SC gap. We show that
the signature of the pseudogap phase which develops during this transition, can
be interpreted as the blocking of charge carriers by the enhancement of the
antiferromagnetic correlations as the temperature drops. We find that the
energy scale of the pseudogap, $\Delta_{\textrm{pg}}(p)$, closely follows the
one of the spin singlet excitation, $\Delta_{\textrm{sse}}(p)$, with doping
$p$. The quasiparticles lifetime considerably increases with doping when the
pseudogap collapses. We reveal that the maximum amplitude of the SC gap,
$\Delta_{\textrm{sc}}^{\textrm{max}}$ and the SC transition temperature \Tc are
linked in an extended range of doping such as
$\Delta_{\textrm{sc}}^{\textrm{max}}(p) \propto \Delta_{\textrm{sse}}(p)\,
T_c(p)$. This relation suggests that the AF correlations play a key role in the
mechanism of superconductivity.
