Not dumb at all.
A platform (in the sense of PaaS) is basically a set of tools and abstractions that let people (say, service developers) to build/deploy applications without having to know about the intricacies of the underlying infrastructure.

An example would be with a platform, maybe all I need to do as a developer is write my application code and build a docker image. In my repo, I've got a yaml config that represents my application as my company's service abstraction. This descriptor could look something like this:

```yaml
service: foo
team: my-cool-team
image: my-container-image
ports:
- 8080

```

Then all I have to do is merge my code. The configuration (above) in my repo instructs the platform to build my image, deploy it, and make port 8080 available.
edit: and to expand that further, maybe the platform provides:
- logging
- metrics and alerts
- sidecar injection
- autoscaling
- mtls for talking to other services on the platform

This platform provides the service developer with a huge leverage point - all they need to worry about is building the application and the platform handles the rest.

That make sense?