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

https://www.unitedbookmarkings.win/tiered-link-building-uses-two-levels-of-links-to-boost-your-site-s-authority-1

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