Here is the whole process.
Use the crank to raise the trap. Shake the plant so that a piece of fruit drops down below the trap. Touch the piece of fruit so that it rolls a bit further.
Walk past the crank, slide down and turn right. Go to the unfurled leaf and pull on the triangular pulley to the right.
The trap will drop, miss the animal but frighten it away. The animal will make noise when crossing the bridge, causing the plants to open and the bridge to collapse.
Now you can walk to the end of the leaf and swing straight ahead on the trapeze to a new location.
God, this one took me awhile to work out!!