I am relatively new to building larger apps. I've worked for a coulple years building with Drupal and hacking PHP. Now I only want to develope full stack JavaScript. I really enjoy it's messy nature. Last week I discovered that user uploaded files are not persistent on a Heroku hosted app. To solve that problem, I created an AWS S3 account which is the first time I've used AWS. I quickly figured out to exchange Node.js fs functions with the AWS SDK. Setting up a bucket and a test bucket easy. And, configuring IAM rules is intuitive.
You're right. Their docs are far beyond the scope of what I needed to get started. Interestingly, I would rather have Google searches about AWS show Stack Exchange answers but most of the first results are all Amazon documentation which is far more difficult to read and sort.