Computing quotients of group by elements of its lower exponent$-p$ central series

Let $ G$ be a finite $ p−$ group of number of generators $ d$ and exponent$ −p$ class $ c$ , that is $ c$ is the smallest integer satisfying $ P_c(G)=1$ in the series $ $ G=P_0(G)≥…≥P_{i−1}(G)≥P_i(G)≥… $ $ Where $ P_i(G)=[P_{i−1}(G),G]P{i−1}(G)^p$ .

1/ Can you show me how to calculate $ G/P_i(G)$ ´s using GAP system?

2/ Can you show me how to compute $ G/P_1(G)$ using abelianisation and row-echelonisation (by hand)?

Thanks in advance