Asus laptop help, please

I have an Asus laptop, a ASUS Eee PC 1015PED 10.1" Netbook. I bought it from a friend. He has about 20 gig of stuff on it. My wife set it up for me to be able to web surf.
My question is: How do I access the stuff still on the laptop, look at it, and erase it so I can use the memory space. Assume I know little to nothing about computers.
Thanks

ASUS Eee PC 1015PED 10.1" Netbook

cheap netbook
newest netbook
buy netbook