Project resources are located in the Assets folder as files. In other words, all files in the Assets folder are considered project resources.
In the usual case resources are created using the New Object window. The window can be opened using the New button in the Ribbon.
The window can be also opened using the context menu of the Resources Window. To do it select the folder in which the resource is to be created. Next open the context menu and use the 'New Resource' item.
After the New Object window will be opened. In the window you need to select a type, a file name and parameters of the creation.
After creation the resource will be opened for editing.