I just started playing From Dust, and I find it rather clunky to control.  While building a bridge as part of the objective, my villagers will randomly start drowning, my village will randomly get hit by a tsunami, lava will pour down the mountaintop, or any number of unfortunate things may happen.  I want to help my villagers, but only seem to hurt them.

What am I doing wrong, or what can I do more effectively to help my villagers?