There are some sample templates available on the Developer website. However, you can also create one in your iCloud storage using Swift Playgrounds app for MacOS if you don’t have an iPad on hand. - Sample Apps

This appears to be a bug in Swift Playgrounds 4.0.2. You are able to drag in the CoreML model, but Swift Playgrounds won’t be able to find it in scope. I also tried this in Xcode 13.2 using the new App Package and had the same result. Xcode normally builds the model based on the inputs, so I tried to extract the model from another build and still the same result. I’m sure this will get fixed soon because it used to work in older Playground Books / Files. I’ve logged the bug also.