Actions

Actions (also called nodes) are the steps in your workflow after the trigger. You connect outputs to inputs to pass data through the graph.

Documentation

Every built-in action is documented by package in the Actions reference tab:

Start with How actions work for inputs, outputs, accounts, and sub-workflows.
Use Nodes by package to jump to Gmail, Sheets, Core, Text, and the rest.

In the editor, add an action from the picker—the same names and descriptions appear there as in the reference.