@creamy-hamburger-70712 I found this confusing when I first started too, here's what helped me. Disclaimer: I'm just an average guy not an expert.
There are three different AWS flavours with Pulumi
• AWS native: this is pulumi developing their own code to integrate with AWS API directly. This doesn't have full coverage yet.
• AWS classic: this is bridged from Terraform provider open source code under the hood. You can do pretty much anything in AWS (afaik).
• AWS Crosswalk: (awsx) This is higher level that abstracts some of the underlying bits to make it quicker and easier to do things. Think of it like a wrapper. Creating an awsx resource will create some underlying aws classic and/or aws native resources, which you can usually reference as sub objects.
As far as I know you can use combinations of them all within the same stack. But you may like to stick to one at the start, because it takes a bit of mental power remembering which ones have which properties and attributes.
If your main focus is learning Pulumi, I'd probably recommend going with AWS Classic to start off with. You'll be able to do everything you need to do without getting confused why some things are not available (like you would with AWS Native) or why things aren't visible (because AWSX hides them).
If your main focus is learning AWS features, then AWSX (Crosswalk) is most useful since it gets you up and running with a working solution (Such as deploying a website using a load balancer in front of an ECS deployed container) with minimum effort.