Here are the few steps to follow to join an organization when an invite was sent to you:
1. Check your mailbox
Open the mail and click on the link which is inside or copy paste it in your favorite browser.
2. Choose a password
Once on the setup page, modify your username as desired and choose a password.
Click on the button "Start using Augment" to complete the step and validate your account.
3. Enjoy Augment
Almost done ! Download the Augment app if needed.
Then sign in to the app or to https://manager.augment.com/
The shared folders granted by the invite will be accessible, otherwise ask for a share link to your organisation account manager.