In AWS Console, go to "Services" drop-down list, "IAM" (Identity and Access Management). On the left-hand panel, choose "Access management" -> "Users", click the "Add user" button, go through the wizard, and as a result you'll have a new user added:
Ensure that this user has "AmazonS3FullAccess" in the list of permissions.
Then, you'll need to create an access key for the newly created user. For that, go to the user description, then to the "Security credentials" tab, and press the "Create access key" button:
Put these credentials to the local file in the home directory ~/aws-credentials.txt. For example: