Folders in the Dock are called stacks. You can use stacks to reduce clutter and quickly access folders of documents, applications, downloads, and other folders. When you click a stack in the Dock, it springs open to display an arc or a grid of icons for the items in the stack. You can scroll through stacks, open folders, and navigate back. The Dock comes with two stacks, the Documents (New!) and Downloads folders, which stores your documents and downloaded items from the Internet. You can create more stacks by dragging the folder you want to the Dock and modify stacks by Control-clicking it in the Dock.
Work with Stacks on the Dock
Display a stack. Click a folder in the Dock.
Open the stack folder. Control-click the folder in the Dock, and then click Open “name” or point to Options, and click Show in Finder.
Open an item in a stack folder. Click the folder in the Dock, and then click the item. If you click a folder in Grid view, you can click the return path icon in the upper left of the stack to return.
Add a stack to the Dock. Drag the folder to the Dock.
Remove a stack from the Dock. Control-click the folder in the Dock, point to Options, and then click Remove from Dock.
Change the stack display. Control-click the folder in the Dock, and then click Automatic, List, Grid, or Fan. Automatic displays in a fan or grid depending on available space.
Change stack icon in the Dock. Control-click the folder or stack in the Dock, and then click Folder or Stack.
Sort items in a stack. Control-click the folder in the Dock, and then select the sort type (under Sort by) you want.