TL;DR: Chain subitems together so they run in the right order — set dependencies between consecutive subitems, propagate date changes down the chain, or anchor a subitem's start to a connected item.
When to use these automations
Subitems must execute in a specific order (dependency chain)
Pushing one subitem's date should ripple to the next subitem in sequence
A subitem's timeline depends on a connected item from another board
Dependency recipes
Recipe (exact text from automation center)
Use when
Deep-dive
"When subitem is created, set previous subitem as a dependency using dependency column."
Each new subitem auto-depends on the one above it. Useful for stepwise workflows.