A canonical URL is the URL of the page that Google thinks is most representative from a set of duplicate pages on your site. Canonical tags suggest to Google which page you think is the correct page to consolidate ranking signals to.
If you have multiple versions of a page for different languages or regions, tell Google about these different variations with Hreflang. Doing so will help Google Search point users to the most appropriate version of your page by language or region.
Install the first snippet as high up in the head of the page as possible, but after the dataLayer code. Install the second snippet at the top of the opening body tag.
A 301 redirect indicates that a URL has permanently moved to a new location and is not coming back.
A 302 redirect indicates that you are temporarily sending users to a different URL and the original is coming back shortly.
A flat site structure is when the majority of pages on a site are a minimal amount of clicks from the home page.
A deep site structure is when the majority of pages are multiple clicks from the home page, resulting in them receiving less PageRank.
Canonicals within a paginated sequence should be self-referential and should also not include the noindex tag in most scenarios.
With a view all page pagination set-up, if pages within the paginated sequence still exist in your CMS, you should canonicalise them all to the view all page.
Topic clustering is a popular internal linking strategy that consists of 'pillar' pages covering a topic that then links out to 'cluster' pages with further details targeting long-tail keywords.
The rel="nofollow" attribute is a hint to Google to not associate your site with the URL you are linking out to and also prevent crawling.
The noindex tag instructs Google to not index and show a page in search results, commonly found in either the head of a page or within HTTP headers.