This is a minimum sample in PHP5.
First edit this file and enter your app's Client ID and Client Secret. Create your own app on the developer portal.
To use this sample you need a model URN. Please upload a model on models.autodesk.io
Specify a model URN:
The model whose URN you paste here must have been uploaded using the same app that is used by this web page.
Unless you modified the code and now it's using your own app's Client ID and Client Secret it won't be able to show your models.
Here is the URN of a model that was uploaded using the app's original keys and so should be viewable: