So how exactly does Google work?
The details of Google's ranking system is a closely guarded (and very complicated) secret. We have some decent ideas of what you need to do to move up the rankings (you can read more about them here), but before a site can even move up in the rankings, it first has to get into Google's index.
This is where Googlebot comes in. Googlebot is constantly crawling the web, looking for new websites, updated content, and fresh items to add to Google's index (it's also looking for things that have moved or been removed). Googlebot finds new content a number of ways, including following links from other sites.
Once Googlebot finds a website, it then has to figure out what pages are on it. You can hope Googlebot can find your site by following links, or you can do some things to help it along. Once it reaches a page, it doesn't worry about ranking it, it simply downloads it into Google's index. From there, another set of services will analyze the page and determine where - and if - it should be shown in search results.