Hi @Dhakshinamoorthy A,
I've created an example model that uses an operator with a "cart" (Task Executor) to load/unload boxes. Your question was kind of vague, but I'm assuming this is what you're expecting in terms of a response. I also took the liberty of creating this model in 19.1 because you didn't specify a version.
To achieve the effect that an operator is using a "cart" to transport objects, there are two main things that you need to do:
1) Use Travel and Move Object activities in Process Flow rather than Load and Unload activities.

2) Move the "cart" object into the Operator object.

The key is accurately placing the Boxes inside the 1st subnode of the Operator, which is the "cart". This model uses labels extensively, so let me know if anything with labeling is unclear and I'll try to better explain it.
Hopefully this helps!
Model: make-operator-use-taskexecuter.fsm