but there is no example to import the orders, customers and products form magento site / mysql db to the qucikbooks using web connector
Yes there is.
This example shows how to add customers and sales receipts to QuickBooks:
There's a more fleshed out example here:
If we queued a process that process won't run instantly right?
Correct. That's what a queue is - a list of things to do in the future.
It will run only based on the time we set for the application in the web connector program like to run every 2 minutes is that right?
Correct.