Got a Morris coupler that connects to the ends of a components.The coupler is then connected to a hollow tube.

The hollow tubing comes in several standard length. Thus, if the tubing is quite long, it will need intermediate Morris couplers.

In the Routing Component Wizard, what should I select for "Route Type" and "Component Type" to accomplish this?

I've tried "tubing" for "Route Type" and then "others fittings > Coupling/Union" for "Component Type." However, dragging and dropping the Morris coupler into an assembly brings up a property manager that doesn't contain the fields "use standard length" and "insert coupler".