Let $\alpha = 0.05$. Let p-value $n \times n$ matrix B. Set zero all values which are less than $\alpha$.
\begin{equation} B_{k}(i,j) = \begin{cases} 0 \text{ if } B_{k}(i,j) \geq \alpha \\ 1 \text{ otherwise} \end{cases} \label{eq:cell} \end{equation}
Is this right?