The Require Contractors to Provide Multi-Tier Contractor Information box in the Tiered Subs section will need to be checked in the Project Settings tab. This feature will allow you to generate lien waivers to the listed vendors in the liabilities tab.
In the Lien Waivers/Templates section of the Project Settings, click + Add Lien Waivers and select a tiered waiver template.
Don't see any tier waiver templates? Please see How do I create a new waiver template?