Start Another Flow step replaces standard ManyChat Go to Flow step. The new step has a connection dot like Action or Condition steps - an admin can use it to choose the next step which will fire after a subscriber finishes the flow selected in Start Another Flow step.
How to create Start Another Flow step?
To create a Start Another Flow step click on a round button in upper-right corner of the screen or just double-click any empty space in Flow Builder. Then select a Start Another Flow from the drop-down list.
Click on the step that appears to open the options menu, then click Choose Next Step to select a flow.
Choose a flow from the list and click on Select This Flow button.
The last thing is selecting a flow or action that will fire to a subscriber after the content from the Start Another Flow step ends. To do that, simply click on the step's connection dot and drag the line to the other step.
Keep in mind that if the connected flow has several branches of content, a user will return back to original flow after reaching the end of any branch.