When opening the timer window (which is not easily done---what area must one right-click? why only right-click at all?) and then trying to add a new timer, the "Add new alarm" window opens *behind* the timer window which is mighty counterintuitive and nonstandard, as then the most of it is concealed and you need to draw it away.
Could you try again with 0.6.4 please? Things work correctly over here.
OK, timer-0.6.4 does away with with the lower window. Still, the panel doesn't change when a new timer (countdown or alarm) is added, and no means to start them are apparent.