I have gone through the AWS console page and cannot find an clear answer:
When creating AWS account and your own AWS services, you need to get a accessKeyId and secretKey from AWS.
What are they and what's the relationship between them? When and how will they be used when running your own AWS service?
You need AccessKeyId and SecretKey for your AWS Account to access resources in your account programmatically. You can get them by creating an IAM User adding necessary permissions to that User. Once the user is created you can find these (accesskey and secretkey) details on the console. This is over simplification of what they are and how you can ge t them. AWS Docs will have much better explanation
