Steps
Open Admin → Workflows (or an area's Workflows app).
Click New workflow. The dialog offers a blank start or one of the shipped templates — see Templates.
Give the workflow a name and short description.
Pick a trigger. The trigger menu only shows events compatible with the current scope.
Optionally add conditions. A workflow with no conditions fires for every trigger event. Conditions narrow the firing.
Add one or more actions. Drag from the action palette onto the canvas; connect from the trigger node.
Save the workflow as Disabled first. Use Test mode to dry-run it.
When you're happy, flip the workflow to Enabled.
Anatomy of a workflow node
Trigger — exactly one per workflow. The "start" node.
Condition — zero or more. Each is one comparison (field + operator + value).
Action — one or more. Connected after the trigger (and after any conditions).
Note — There is no built-in AND/OR clause aggregator in the builder UI today — to combine multiple conditions, chain condition nodes one after another (effectively AND), or use multiple parallel branches off the same trigger (effectively OR).