Follow these steps

Start by visiting the project pages that are listed in the comments of this issue. (All of the projects have their privacy set to Everyone which means that even a signed-out-person can view them in View Only mode)
Sign up for a user account on http://staging.makerble.com by going to https://staging.makerble.com/users/sign_up (if you haven't done so already)
On Staging: Create an Organisation (use the charitable organisation that you came up with in the Design1 exercise https://trello.com/c/C6WXYxyI/354-design-1-create-your-own-measure-the-difference-plan-1-hour)
On Staging: Follow another user (a list of users to potentially follow is in the Comments of this card)
Add your user profile as a comment to this card
On Staging: Create two projects (use the projects that you came up with in the Design1 exercise https://trello.com/c/C6WXYxyI/354-design-1-create-your-own-measure-the-difference-plan-1-hour
Set the privacy of your projects to Everyone: click the padlock button at the top of the project page and set it to Everyone
Copy the url of your project and paste it as a comment in the trello card

How to video