The easiest way to test out morphs and how they work is to;
create your morph target.
go to scene mode->build->add object and bring in the object that has the morph target with it.
Now, click the "Key Icon" to start the keyframing.
In the area in the bottom where you can choose what frame you are on, hit the "plus" signs until you see the name of your object, then expand the object by hitting that plus sign. You should see the morphtarget name there.
In this area, double click this morph target.
You will see the keyframe box pop up.
Click, "add keyframe" for "frame" make sure it shows "0" and for value, You can leave this at 0.
click ok.
Now double click again, to open the keyframe box, add another keyframe. make "frame" say 71 and put 1 for the value field.
click ok.
Now go ahead and play your animation and you will see the morph.
From what I understand 0 is neutral (so whatever your object looked like before adding a morph target), 1 means a hundred percent. You certainly can use other numbers between 0 and 1 to get anything in between, but you can also use numbers high than 1, and even negative numbers. Just experiment a little bit with it.
Hope this helps
Sage