Keep walking; you'll find something of interest eventually.
If you don't turn right for your first two junctions, you won't go wrong.
Fairly soon after you see a spherical purple plant, you'll be able to turn left or go straight. You can go either way; if you go straight, level 1 will go faster, but if you go left the puzzle will make more sense. The choice is yours.
I went left. What do I do now?
I went straight. What do I do with the purple reflector?
Oops - I need to get back up to the big tree. How do I do that?
Can you explain what I'm actually trying to do on this level?