We won't do homework for you here. If you have a specific question (preferably one about these topics in general, not solving this HW assignment), we can discuss it.
Syntax trees are unambiguous because they clearly represent groupings of words (as constituency).
One way to approach this is to make a tree for the sentence and then figure out what reading it represents. Then work out what the other tree would look like.
As a practical approach (that you might or might not find intuitive), you can ask yourself: what does the [ambiguously attached part of the sentence] modify? That's a start.
A common example is:
The man saw the dog with the binoculars.
We can clarify the ambiguity using bracketing:
The man [saw the dog] with the binoculars.
The man saw [the dog with the binoculars].
Bracketing like that is equivalent to tree structure (plus whatever other structure is needed to make the full tree of course).
Any more help beyond this would be too much for this assignment and take away your chance to learn with it.
