Search engines use complex mathematical algorithms to interpret which websites a user seeks. In this diagram, if each bubble represents a website, programs sometimes called spiders examine which sites link to which other sites, with arrows representing these links. Websites getting more inbound links, or stronger links, are presumed to be more important and what the user is searching for. In this example, since website B is the recipient of numerous inbound links, it ranks more highly in a web search. And the links "carry through", such that website C, even though it only has one inbound link, has an inbound link from a highly popular site (B) while site E does not. Note: Percentages are rounded.
QUOTE: “So if you have different parts of your website and they’re on different subdomains that’s that’s perfectly fine that’s totally up to you and the way people link across these different subdomains is really up to you I guess one of the tricky aspects there is that we try to figure out what belongs to a website and to treat that more as a single website and sometimes things on separate subdomains are like a single website and sometimes they’re more like separate websites for example on on blogger all of the subdomains are essentially completely separate websites they’re not related to each other on the other hand other websites might have different subdomains and they just use them for different parts of the same thing so maybe for different country versions maybe for different language versions all of that is completely normal.” John Mueller 2017
QUOTE: “For the mostpart it should be fine I think the the tricky part that you need to be careful about is more around doorway pages in the sense that if all of these pages end up with the same business then that can look a lot like a doorway page but like just focusing on the content duplication part that’s something that for the most part is fine what will happen there is will index all of these pages separately because from from a kind of holistic point of view these pages are unique they have unique content on them they might have like chunks of text on them which are duplicated but on their own these pages are unique so we’ll index them separately and in the search results when someone is searching for something generic and we don’t know which of these pages are the best ones we’ll pick one of these pages and show that to the user and filter out the other variations of that that page so for example if someone in Ireland is just looking for dental bridges and you have a bunch of different pages for different kind of clinics that offer the service and probably will pick one of those pages and show those in the search results and filter out the other ones.
The emphasis on tools, meaning plural, is important because there's no one magical way to plop your website atop every single search results page, at least not organically, though there are best practices to do so. If you want to buy a paid search ad spot, then Google AdWords will happily take your money. This will certainly put your website at the top of Google's search results but always with an indicator that yours is a paid position. To win the more valuable and customer-trusted organic search spots (meaning those spots that start below all of those marked with an "Ad" icon), you must have a balanced and comprehensive SEO strategy in place.