The general process for adding flows is described under Manage flows - Documentation - Confluence (atlassian.net)
To add a rule with weights settings, you need to use an object flow type.
The transaction distribution rule can be added to a new flow as well as to an existing flow that has an object type.
The flow containing the transaction distribution rule must be placed last in the flow list for a shop so that it’s applied last in the sequence of flows. To do this, make sure Priority field under Edit Flow area has the maximum possible value.
