For preparation: If your apples are really waxy, it is best to remove the wax first. There are a couple of methods, such as scraping it off or dipping the apples in boiling water for 5-10 seconds and then drying the apples. This will help the caramel stick.
Remove the stem from the apple and carefully stick the candy stick into the center going downwards. Be careful not to pierce all the way through the apple.
In a small pan on the stovetop, heat the caramel candies and salt over medium-low heat, stirring until smooth. Add ½ - 1 tbsp of milk as needed to thin it slightly. Allow the mixture to come to a gentle simmer.
The caramel will be thin. Allow it to rest for a minute or two until it's slightly thicker. Transfer the melted caramel to a heat-safe bowl. Make a tester apple: Take one of the apples and carefully dunk it into the caramel. If the caramel is very thin and easily slides off, you need to let the caramel cool a little bit longer.
Once you’ve found the right consistency, dip the apple 2/3 of the way, turning it and shaking it slightly. (You can also use a spoon to apply it instead of dipping) Scrape the bottom of it on the bowl to remove excess caramel. If using, apply sprinkles. Transfer the tester apple to a sheet tray lined with parchment paper and allow it to set. Continue the process with the other apples, monitoring the caramel’s consistency and reheating it if it thickens too much.
Let the apples rest for a bit until you can easily peel them off the parchment paper. I noticed that the sugar-free caramel I used started to droop off the apples the next day, but it made for a delightful treat that was perfect for enjoying the same day.