These steps need to be done on the main AWS Account. The same one where you have your current AWS Credits. We will create the AWS Organization and all sub-accounts from this one.
1. Sign in as the IAM console at https://console.aws.amazon.com/iam/.
2. In the navigation pane, choose Users and then choose Add user.
3. For username, type your desired username.
4. In select AWS access type, select Programmatic access or AWS Management Console access.
5. In Console password, select Autogenerated or custom password. Make sure to put a check mark on require password reset.
6. Choose Next: Permissions.
7. On the Set permissions page, choose Attach existing policies directly.
8. Choose AdministratorAccess.
9. Choose Next: Tags.
10. Add metadata to the user (optional).
11. Choose Next: Review to see the list of group memberships to be added to the new user. When you are ready to proceed, choose Create user.
12. Take note of the AWS console link to sign in and you download the .csv file.