In order to obtain Friedmann equations, we use the metric $g_{\mu \nu}$ and some metric dependent component, i.e Ricci (curvature) tensor and Ricci scalar. Plugging these and energy-momentum tensor $T_{\mu \nu}$ into Einstein field equations yields two equations.
$\textbf{Temporal Part:}$ \begin{align*} R_{00}- \frac{1}{2} R g_{0 0} = \frac{8 \pi G}{c^4} T_{00} \\ -3 \frac{\ddot{a}}{a} + 3c^2 \left[ \frac{\ddot{a}}{a} + \left(\frac{\dot{a}}{a}\right)^2 + \frac{k}{a^2} \right] &= \frac{8 \pi G }{c^2} \rho \end{align*}
\begin{align} \label{eq15} \boxed{\left(\frac{\dot{a}}{a}\right)^2 = \frac{8 \pi G}{3} \rho - \frac{kc^2}{a^2(t)}} \end{align}
$\textbf{Space part:}$
\begin{align*} R_{ii}- \frac{1}{2} R g_{ii} = 8 \pi G (-p)g_{ii} \end{align*} \begin{align} \label{eq16} \boxed{\frac{2\ddot{a}}{a} + \left(\frac{\dot{a}}{a}\right)^2 = -\frac{8 \pi G }{c^2}p - \frac{kc^2}{a^2(t)}} \end{align}
However, I do not understand that how can time component have a corresponding element ($\rho$) in energy-momentum tensor. By the way I derived $T_{\mu \nu}$:
\begin{align} \label{eq13} T_{\mu \nu}=(\rho + p)u_\mu u_\nu +pg_{\mu \nu} \end{align} where $g_{\mu \nu}$ is the metric of the manifold and $u_\alpha$ is the 4-velocity of the medium.
I mean it is just "time", how can it determines the evolution of the universe? Although I am using first Friedmann equation, I can not understand the issue discussed above.