The app uses recipes to turn your DiceKey into passwords, seeds, keys, and other secrets. It combines the recipe with your DiceKey using what is known as a one-way function. The one-way prevents someone who you share a generated secret with from learning the DiceKey you used to generate that secret. Even the tiniest change to your DiceKey or recipe will completely change the secret, so you will need both to re-generate more secrets in the future.
Because recipes are useless without your DiceKey, your recipe doesn't need to be kept secret. You can save it in the app and not worry that someone can access it, so long as they don't have your DiceKey. Unlike your DiceKey, your recipe will not be stored anywhere permanent and will be lost if you lose the device with the app in which your recipe is saved. That's why we try to encourage you to use very simple recipes that are easy to reproduce.
For example, if you need a password for your password manager or a major email provider, we probably already have a built-in recipe for you. If not, you can create a recipe just by pasting the URL or domain name of the site or app you need secrets for. You can add a sequence number if you need more than one recipe for the same application, but we recommend you only use numbers you can count on your fingers so that you can try them all if you forget which one you needed.
Your app is just a tool for using your DiceKey. You can get a new device, download the app, load in your DiceKey from its physical form, and be no worse off.
The only data you will lose are any recipes you have saved (see the above question about recipes). In most cases, re-generating a recipe should be as simple as picking from the list of built-in recipes or copying the URL or domain name of the site you need a password or secret for into the recipe builder.