You must have other type of applications created to be added in 'Tab' application.
After create your apps, lets create an Tabs app.
When created go to: Tab—> Folders Settings
On textbox (Label) type an name for the first 'Tab'. In my example i've used Tab_01 and then click in Add.
Insert many tabs as you want.
Now, we will link tabs with your apps.
Go to: Tabs —> Applications Settings.
Each tab created will be showed. You just need to click in Add and select which app will be linked.
*PS: In case that you are using an global variable between applications, you have to mark option Reload iframe.