Tiered link building helps you build a strong backlink profile by layering...

https://station-wiki.win/index.php/How_Do_I_Build_Tier_2_Content_That_Looks_Natural_and_Not_Forced%3F

Tiered link building helps you build a strong backlink profile by layering links. Tier 1 are your main backlinks pointing directly to your site. Tier 2 links support Tier 1 by linking to those first-tier pages