How do i fresh install on used OSX 10.6.8?

I just bought a used macbook and i want to wipe it clean to start fresh. it didnt come up a dvd or anything.

I tried following another post on here that said to push Option on start up and it sounded like it could do a fresh install using an internet connection. However when i did it the only icon i got was the hard drive in the laptop.

It looks like you can purchase the dvd on the apple website (http://store.apple.com/us/product/MC573/mac-os-x-106-snow-leopard) though here it looks like it offers a free upgrade to http://www.apple.com/osx/how-to-upgrade/ 10.10.1

though Its not clear if that applies to me since im not the original owner. It's also not clear if i'll run into complications in general since im not the original owner (eg is the laptop tied to someone elses itunes account right now?)

its also not clear if itll allow for a "fresh installation". I'm more of a PC guy i'm not really familiar with macs. What route should I go to wipe the laptop?

thanks