You can use vertex, change tangent, and connector controls to adjust the routing of flexible ducts.
Vertex () appears along the length of the flexible duct and allows changing the point where the duct bends.
Change Tangent () appears at the start and end of the flexible duct and allows adjusting the tangent of the first and last bend.
Connector () appears at each end of the flexible duct to allow repositioning the end of the duct. It allows you to connect the flexible duct to another mechanical component, or disconnect the flexible duct from the system. Right-clicking a connector displays a context menu containing options that let you add or remove a vertex, and when disconnected from another component, lets you draw (connect) rigid ducts and flexible ducts.