Installing the Thule cargo box on the Sienna is easy for two persons and challenging for one person. The trick is to avoid scratching the car.

This is how I do it single-handedly.
1. Carry box from garage to the driveway (awkward but not difficult).
2. Set the rear end of the box on the pavement.
3. Lean the box against the cotton rug.
4. Lift the box onto one of the rack's rails and push it up onto the rack.
5. Swivel the box into position.
6. Remove the rug and attach the box to the rack.

I had to install the cargo box for a five-day drive to Phoenix. I was driving to join my wife and the five-day duration was needed to comfortably transport a cat and bird with me.