How do you calculate the norm of a function describing a molecular orbital?
I'm unsure if you're meant to solve this via the Hückel molecular orbital theory (see Chemistry LibreTexts), however, if you need to calculate the norm of a wave function $\Psi$, this is $|\Psi |$. Given what we know in your post about both $\Psi_{1, 2}$ then
\begin{align}
  |\Psi_1|^2 
    &amp;= \langle\Psi_1 | \Psi_1\rangle \\
    &amp;= 2\cdot(0.602^2)+2 \cdot (0.372^2) \\
    &amp;= 1.001576 \\
  \to |\Psi_1| &amp;= 1.000788 &gt; 1\\
\end{align}
I write that this is greater than one, as, on closer inspection,  is down to rounding from the coefficients of each $p_z$ orbital.

The repeat process can be found for the overlap part, which I am interpreting as $\langle\Psi_1 | \Psi_2\rangle$.