Practice blowing the ink droplets first on a scrap paper.
Drip a drop of indian ink at about one third from the bottom of the sheet and blow through the straw to the top of the sheet and to the sides. Keep blowing to get smaller branches. Make three trees this way.
Let your work dry. Paint a background with watercolour paint. You can paint over the trees carefully, the indian ink will not smudge if it's dry enough. Let the work dry again.
Take tempera and a q-tip to paint autumn leaves on the branches, the ground and in the air. Near the tree many leaves, further less leaves.
Paste your work on a black sheet.