Your website will be a collection of a few, or perhaps several hundred pages. Google needs to know which ones YOU consider to be important enough to “crawl” (or scan, as humans would see it) and how often it should do so. That’s why you give Google a site map.
The site map is a simple file called “sitemap.xml”, and it exists right in the same folder as your homepage (index.html, index.htm, index.php, etc). Below is an example of a sitemap, and once you see it, you will understand why Google likes to find them where they belong.
This sitemap is for a brand new project, so none of the customizations have hit the settings yet. But, from the list, you can see that the page priority (which pages Google should scan first if the robots only have a limited amount of time), the suggested return frequency for the robots, because that’s how often you think you might be changing the content of pages, and the date of the last change to the page. Naturally, the column on the left is the direct URL link to the page in question.
If you look at your root folder, or public folder, and do NOT see a sitemap, you are basically surrendering a huge amount of tactical advantage to your competition. Don’t do that. Generate the sitemap and be serious about what you ask Google to do with it. Don’t make every page a 100% priority. Your “contact” page isn’t going to change very much. It shouldn’t be ranked equally with your “Latest News” page, which could change daily. Google also doesn’t like being lied to. Never forget that.
For example, if you are writing one blog post per week, and that blog post appears dynamically on your homepage, then you should tell the search engines to come back and rescan (recrawl) your home page at least once per week. The sitemap will automatically generate the new page (or at least it should if you’re doing it right), and so Google will find your new article by virtue of its creation date. If this is a really important article, then giving it a 100% may be appropriate. If it’s a story about a customer’s dog that greeted you nicely, eh… not so much.