After you set up the base layer for a reference machine, you can capture a base layer from it so that endpoints can be updated with that content.
The base layer capture process creates a point-in-time snapshot of the data and state of the live reference machine, generalized for mass deployment.
A similar process is employed to capture app layers.
You can use a custom post-base layer script called post_core_update.bat to perform certain actions after the base layer update.
For more information, see the VMware Mirage Administrator's Guide.