Tiered link building uses two levels of links to improve your site’s ranking....

https://wiki-room.win/index.php/How_Do_I_Set_Goals_for_a_Link_Building_Campaign_Without_Guessing%3F

Tiered link building uses two levels of links to improve your site’s ranking. Tier 1 links point directly to your site and are high-quality. Tier 2 links support those Tier 1 links to boost their power