This article explains how tiered link building works by using Tier 1 links to...

https://delta-wiki.win/index.php/What_Anchor_Text_Should_I_Use_for_Tier_1_Links_Without_Overdoing_It%3F

This article explains how tiered link building works by using Tier 1 links to point directly to your site and Tier 2 links to support those Tier 1 sources