Quoting from the Introduction to the Toolkit:

"The employer toolkit contains relevant materials for you and your employees, including a practical
communications plan. These can be downloaded and used before the EU Settlement Scheme goes live.
The Scheme will be phased in later this year, and will gradually open more widely until it is fully open
by the end of March 2019."

Materials provided in the toolkit for employers to share with employees include presentation outlines. how-to animations, videos, leaflets and posters.

Inquiries can be directed here: settlementschemetoolkit@HomeOffice.gsi.gov.uk.

Looks like a massive new workload for both the Home Office and employers. And a big-time stressor for employees who are citizens of EU countries.