To double-click, tap twice.
To drag an item, double-tap but don't lift your finger after the second tap. Drag the item where you want it, then lift your finger to drop.
If your touchpad supports multi-finger taps, right-click by tapping with two fingers at once. Otherwise, you still need to use hardware buttons to right-click. ...
If your touchpad supports multi-finger taps, middle-click by tapping with three fingers at once.