In a large drinking glass, place the ice cubes (how every many you like in your drink). Since they are made of juice, they will not dilute the drink.
Pour in the pineapple juice. Fill the glass the rest of the way with ginger ale.
Thread a pineapple chunk, then a cherry, and another pineapple chunk on a toothpick. Sprinkle on a pinch of ginger for color, not much, though. Garnish the drink. (You can skip this if you don't want to go to the trouble if it's just you.).
NOTE: When making a bunch (say, six), fill each glass with the pineapple juice, then the ginger ale. It wastes time to make each glass individually, having to pick up each ingredient a half a dozen times. Also, you can pre-make a ton of the pineapple ice cubes (ginger ale ice cubes don't really work as well, but you could mix the two liquids and make the cubes using 2 parts ginger ale to one part pineapple juice and freeze) prior to your party and store them in zip-top bags and pre-assemble the garnish sticks. I just use canned pineapple and a jar of cherries.