Where to cut? Always cut where the leaf nodes (this is where future leaves will emerge) are "stacked" (see (1) below). Never cut where leaf nodes are more spread out/far from each other (see (2) below). This distance between two (leaf) nodes is called the internode.
(Btw, I have no clue, why I made those arrows below ;-) ).
But why do we like short/small internodes in the first place (= "stacked" leaf nodes)? Because 1) this is another way of saying, that the plant has a most desired compact growth form,
... and 2) pruning at such a sweet-spot (again, where the leaf nodes are "stacked") can result in several new branches emerging from that particular sweet-spot hiding the cut even from early on. On the other hand, if you prune at (2), you could end up with only a single branch emerging near the cut (= not very pleasing to the eye. Actually, you didn't achieve anything or very little).
Q