You can convert a rule flow to a main flow when you want the execution of the Flow Ruleset to start with the Main Flow.
Locate the flow ruleset (Where is my flow ruleset?) .
Expand the flow ruleset node, the Rule Flows folder and in the context menu of a rule flow node choose Set as Main Flow .
In the dialog box that appears, choose Yes .
You can have only one main flow in a flow ruleset.