To add an existing workflow to a schema, navigate to the Automation tab within the schema's settings, then select 'Add Workflow'.
The trigger for this workflow must first be defined.
If one or more attributes are being updated, you can search for an attribute name by entering this in the 'Filter attributes' search box. Alternatively an entire attribute set can be selected by clicking the 'toggle' button next to the attribute set name.
Once the trigger has been selected, an existing automated workflow must be assigned.