We will explains how the assets are used in Cocos Studio in this page
Cocos Studio supports a variety kinds of assets, you can
(1) import the assets through menu
You can use the Cocos Studio menu "file - Import assets" or the assets panel menu item "import".
(2) drag
You can drag and drop assets directly, into asset panel, canvas, properties panel (onto an attribute) and animation panel.
(3) import through the properties
when you editing the property of a widget. Cocos Studio will copy these assets to your project directory.
The assets you imported will eventually be used to the property of widget. For example, the image widget, asset is used as its attribute "image assets". Widget properties refer to how to use the widget.
(1) publish assets
You can use the publish function to publish your project, Cocos Studio publish the assets to the specified directory, for developers to use. About the publish function, please refer to publishing.