Hi Pierre-Max pPlease follow these below steps (it's a bit longish, but works well):
1.Log in to your Production environment
2.Go to Setting> Applications> Developed Applications and click “New Application”
3.Fill out the form and click “Add Customizations”/ “Add Mailboxes”
4.Select the new customizations you would like to include in the migration and Click “Save”
4.Click “Publish” on the newly created application
5.From the pop-up message, copy the applications’ URL into a new browser and click enter
6.The URL will update itself
7.Add &exp=true at the end of the URL – this will prompt you to save the application
8.Save the file on your hard drive *Additional information can be found in this video tutorial on applications
Import
1. Log in to your Training Box Environment
2. Go to https://app.clarizen.com/Clarizen/Pages/Customization/ImportApplication.aspx
3. Choose the file you saved on your hard drive
4. Click “Import”
5. Install your imported application