Right-click on an empty place on the taskbar -> Unlock (if necessary). Click
on an empty place, hold down the left mouse button an drag the taskbar to
the edge where you want it (bottom, in your case).
Right-click on an empty place on the taskbar -> Unlock (if necessary). Click
on an empty place, hold down the left mouse button an drag the taskbar to
the edge where you want it (bottom, in your case).