Toolbar contains buttons for all operations which can be applied on selected transfer. Not all are enabled at all times. For example you cannot pause already paused transfer. These buttons are grouped together according to their functions.
Left part contains buttons for basic operations. These are Resume, Pause, Delete and Pause all buttons. Their functions should be already obvious.
In the middle part there are three mode toggle buttons : Queued, Scheduled and Delayed. They show the current transfer mode for selected transfer. Use them to quickly change the transfer mode. These buttons are like radio buttons, only one can be selected.
Third part contains two buttons : Preferences, for quick opening of preferences dialog and Paste transfer for pasting of the URL into the Caitoo.
Fourth part contains five global toggle buttons : Expert mode, Use last directory, Auto-disconnect mode, Auto-shutdown mode and Auto-paste mode.
The right most toolbar button is for docking. It's a toggle button. When you turn it on, Caitoo will dock into the panel. See Dock Widget.