I understand the layman concept of PACF - it is the correlation with the linear dependence of the earlier lags removed.
However, I am confused as to how this relates to Autocorrelation. Consider ACF(2) which is equal to corr(Xt, Xt-2).
Where and how is the correlation between the earlier lags included in the computation of this value? How does Xt-1 come into the picture? I have read explanations involving vectors and residuals but it’s still difficult to comprehend. Could someone explain this more simply?