Getting started with IAM on AWS? Have a look at this excellent resource freely available directly from AWS. Deep Dive with Security: AWS Identity and Access Management (IAM) https://www.aws.training/Details/eLearning?id=53780
A few things you should do first with IAM. Begin by securing your root account. Don’t use your root account for operations beyond setting up your first IAM administrator account for your needs. Enable MFA on both your root account and the IAM administrative account.