Step by step

Cut the apples into cubes and mix with the juice

Tips
As for the choice of apples to use, bear in mind that if you want to have a little sharpness in your dessert, you should opt for green apples, or Granny Smiths; but if you want a sweeter jelly, choose sweeter apples such as the common yellow apple.
Trivia
Grape juice can be made with a simple extractor that crushes the grapes and extracts the juice that can then be pasteurized and stored.