To begin with, at the very basic level remind yourself that as a parent, God knows your heart.
Please be encouraged that being mindful of this subject is already a step in the right direction. Pray that your children’s hearts and minds will be open. Being ready to receive the story is a great place to start.
For younger children, I have found focusing on the resurrection piece works best. As they get older they will learn more about the heavier details and process them step by step.
For preschoolers and toddlers, some of the details about the torture Jesus endured would most likely be hard for them to process and move past. Quite frankly, it would scare them more than it would impress upon them the significance.
Realize, that this is just a start for them. Keeping it simple is best!
Jesus died and rose again so that we could have life after death. If you are struggling with the words, one of the simplest things to do is to read the story from a children’s Bible. Many of them have simple words and pictures that will help guide your discussion.