Now that all of your tasks have been accomplished, you can log out from the root user and start to use the IAM user with the administrator rights that you have created, as follows:
If you are completely new to the cloud approach, it is worth spending some time reading the AWS Shared Responsibility Model at https://aws.amazon.com/compliance/shared-responsibility-model/. On the page, there is a clear definition of what AWS's responsibility is (security of the cloud), and also, what our responsibility is (security in the cloud). In a few words, it is our responsibility to ensure that what we create inside of the cloud, ...