I'm still struggling with navigation bars and just can't work out how to edit or verify that I have a navigation bar on my view and I would appreciate any help.

I have a project with another set of scenes similarly comprising of a navigation controller and three associated view controllers (connected via segues and main table view embedded in the navigation controller) and I was able to add a navigation bar manually in interface builder to the outer view controllers that were segued to the table view controller.
*But in this set of scenes the navigation controller is set up as the root view controller for the table view.*

I have another set of scenes. A navigation controller and two related view controllers - both table view controllers. I embedded the first table view controller in the navigation controller and I then added a second table view controller to this (for a new screen I want to add to my app) and I connected this second table view controller to my first table view controller by way of a show segue (just like I did yesterday with other set of scenes).
*Can I set this other navigation controller as the root controller also?
Like, can I have two root view controllers in a project?* 

It looks to me like there is a navigation bar visible (see screenshot below) on my new table view controller but I can't click in to it to edit it to add a title to it.
But does a navigation bar and exist, and if so, why can't I click inside it and use it?

I was told in an answer to a previous question that you have to add a navigation bar manually to your storyboard scene to any additional view controllers. I did that yday and it worked. But today when I tried to add a navigation bar by dragging onto scene it wouldn't let me do this.

Here is the screenshot:
![enter image description here](https://i.stack.imgur.com/Z9Hhb.png)