Scene not showing up when selecting asset files in the package upload menu

Hello. I am trying to publish an asset of mine on the store. That asset includes a scene that works out of the box to show how to use the files of the asset. However, when I try to upload the package from the asset store tools menu, the scene, and only the scene, doesn't appear in the file tree, so I can't select it !

Why doesn't it appear ? How can I change t$$anonymous$$s ? Can't I simply upload a .unitypackage file instead of selecting all the files ? Thanks for your help.