How to convert NPDA to PDA?
Suppose your stack alphabet is $\Gamma =\left\{Z_0,X\right\}$. You can eliminate transitions which don't pop stack, by guessing which stack symbol is at the top. like this:

before: 
$(a,\epsilon)/XXX$

after: 
$(a, X)/XXXX$, and 
$(a, Z_0)/XXXZ_0$