I am developing an application designed to create the following navigation structure. I need to have a welcome view with the "Register" and "Login" buttons, since most applications have:

The navigation bar does not appear in this view, as it seems to be a common thing. If "Login" is listened, then the login view will be presented modally:

And if "Register" is clicked, the welcome view goes to a form requesting user input to create an account:

Then, as soon as the user logs in and logs into the application, I would like to have side menus similar to Facebook, YouTube or Spotify:

Being the central panel of a UINavigationController . The left sidebar, I think, is usually a "UIViewController" ...
The thing is, I don’t know what the rootViewController my application should be, and what hierarchy of view controllers I should have. I thought of several possibilities:
1) From the rootViewController an UINavigationController , click on the welcome view, hiding the navigation bar (is this possible?), rootViewController “Login” view if necessary or by clicking “Register”. After the user has logged in, place these views from the rootViewController , that is, the UINavigationController , and then click on such a navigation controller the user view controller that controls the side menu file.
2) Being the rootViewController user side rootViewController controller and setting its central UINavigationController panel. Click on the welcome view, etc., Without setting any view controller for the left / right panels, and then, when the user is logged in, cover these views from the UINavigationController central panel, click on the corresponding view and now set the panels on the left / right
Hope I explained it myself. Perhaps there is a different and better approach to solving this scenario. Has anyone implemented such an application? I need help in this matter, and I would also be grateful if you would be recommended a special library / control that provides material from the side menu from the one who used it, and it is easy to use and configure. I know that there are many of them ( MMDrawerController , JASidePanels , for example), but I would like to get some opinions from the people who developed the application with one of them.
Note. I also need to support an iPad, and iOS 5+
Thank you so much