[pistol] Adobe Elements 11 Help!

I have recently gotten back into making art on my PC since I got my Wacom Intous Pro Back out. Problem is, I am not sure on many of the abilities of Adobe Photoshop Elements 11!

I'm sure many of you use this or have used this program, so I'm seeking some help from ya'll.

1. When I download a greyscale, some of the layers are put into folders. How do I open them or undo them so I can paint on it? (image 1)

2. Is there a way to make non-transparent linearts transparent so I can color beneath them? (Image 2/3)

3. How do I download brushes?! I've done it once but haven't gotten it to work ever again. If you could explain it simply or link me to a tutorial that would be fantastic! 

Image 1

Image 2/3