Don't be scared by rule of thirds.
If you still do not understand, just ask you tutor, they will be happy to help, it is their job after all.
but rule of thirds.
for landscape.
put the "ground" up to about the first horizontal line, then water, mountains or w/e to the second line, then sky up to the top.
and maybe have a tree, log, driftwood, bird or something to the right or left on one of the crossing points, that way you have used the rule of thirds.
but dont learn to use it all the time, it isn't always a good guide line, sometimes (for portrait.) it is best to center your subject.
just use RoT in situations it will suit (wide spaces and thing like that, i.e. taking a photo of a street, capture someone walking through on one of the crossing points.
hope that helped rather than confuse, but all the advice in this thread is pretty much dead on.