Most often you want to have structure in which you can store your contents in. This is done with folders in Infoglue. A folder can contain other any number of folders and contents so you can create your own hierarchies any way you want.
To create a new folder you either right-click on a place in the tree where you want it and select the "Create folder"-option in the menu. Or you click on the same folder and use the toolbar button under "Create folder"(drops down under "Create content").
The dialog is the same. You just state a name and publish / expire dates and then press the "Save"-button.
The new folder should be visible in the tree and selected in the main area.