How to link Accounts to OU to Root

Thank you for your question about setting up your AWS organization structure. I'll address your concerns and provide guidance on how to properly set up your accounts, Organizational Units (OUs), and Resource Groups.

1. Root and Initial OU: When you create an AWS Organization, a root is automatically created, but it's not an OU itself. The root is the top-level container for all accounts and OUs in your organization. You don't need to create a Resource Group for the root.

2. Adding Accounts to OUs: To add accounts to an OU, you need to move them from the root (or another OU) into the desired OU. Here's how:

• Sign in to the AWS Organizations console using your management account.
• Navigate to the AWS accounts page.
• Select the account you want to move.
• From the "Actions" menu, choose "Move".
• Select the destination OU and confirm the move.

3. Creating and Linking Resource Groups: Resource Groups are created and managed at the account level, not at the organization level. They don't directly link to OUs or the root. Instead, you create Resource Groups within each account to organize resources in that specific account.

To set up the structure you're aiming for:

1. Ensure your root organization is set up (which it seems you've done).
2. Create OUs as needed under the root.
3. Create or invite member accounts.
4. Move accounts into the appropriate OUs.
5. Within each account, create Resource Groups as needed to organize resources.

Remember, the hierarchy goes: Root > OUs > Accounts > Resource Groups (within each account).

As a new company using AWS, I recommend you take some time to plan your organizational structure carefully. Consider factors like your company's departments, environments (e.g., development, testing, production), and any compliance requirements you may have. This will help you create an efficient and manageable AWS organization structure.
Sources
Moving accounts to an organizational unit (OU) or between the root and OUs with AWS Organizations - AWS Organizations
Creating an organizational unit (OU) with AWS Organizations - AWS Organizations
Configuring account structure and OUs - AWS Prescriptive Guidance