Hello, I have a lot of documents on my mac and theres so many ads that keeps popping up (this is not happening on my macbook air). So I was wondering how to "restore my mac". I searched online how to do it, but I didn't really find a way. I know that there is a way to do so on iOS device, to erase every single thing on the device. An I won't back it up since all of the document I need are in iCloud (pages, keynote documents)... So what I wan is to restore the mac just like when I bought it. THANKS IN ADVANCE!!