.GetPage returns a page of a given path. Both Site and Page implements this method. The Page variant will, if given a relative path – i.e. a path without a leading / – try look for the page relative to the current page.
This method will return nil when no page could be found, so the above will not print anything if the blog section is not found.
The previous examples have used the full content filename to look up the post. Depending on how you have organized your content (whether you have the language code in the file name or not, e.g. my-post.en.md), you may want to do the lookup without extension. This will get you the current language’s version of the page: