There are many different routing possibilties depending on how your customer runs their business and their day-to-day business processes. Here is some things to take into consideration when designing call flow specifically around where to place call queues in your routing strategy.
Call queues are meant to be placed in an "end game" senario. If you have a very complicated or elongated inbound call routing scheme call queues shouldn't came early in the the process.
Example: Imagine a call flow where a single call could go through this process
The problem here is that routing a large volume of calls through a call flow like this will almost certainly present situations where calls get "lost" somewhere along the route.
Example: A better way to place the call queue
In a best case senario calls that go to Queues should almost always end up in a voicemail which is why you want to strategic place them towards the end if not at the very end of a call routing scheme