Navigators are the only component that you cannot drag and drop into your phone at the moment. You'll have to drag it left to the tree hierarchy. Make sure that screens are fully contained within your navigator.
Name your Tab(s)
To name your tabs, you'll have to navigate to the properties for your Screen
Tab Bar Label
Title of your Tab
Set Tab bar to the top or bottom of the screen
Tab Bar Position
Default (top); Other option is bottom; On Android, we recommend setting the tab bar on the top; for iOS, we recommend placing it on the bottom
Swiping is a popular way to move through screens and is enabled by the Tab Navigator
Default (false); If true, enables screen navigation by swiping
Hide Tab bar
To hide the Tab bar, you'll actually have to change a Screen property
Tab Bar Visible
Default (true); If false, Tab bar will not be visible
Adding icons to Tab bar
Currently, it is not yet possible to add icons to your tab bar for iOS. We are working to add this feature soon.