For storing your training data, please follow the instructions provided for Type 1 challenges.
For storing your testing data, data storage differs a lot from that of a Type 1 challenge. Instead of hosting your dataset in a public repository, you need to upload your private test set to a private archive on grand-challenge.org. Ensure to not set this repository public as this is your private/hidden test set that should not be made available to participants.
This archive is then linked to the respective phase in your challenge by one of the site admins (send an email to firstname.lastname@example.org to set this up). Running algorithm submissions on this archive then works automatically and is taken care of by the website without requiring any further input from your side. More instructions on creating an archive can be found here.
⚠️ Note that you need one separate archive for each of the phases of your challenge.