Each tab can contain multiple modules as well as an html/text area above. In this example I've added some html/text to Tab 1 and included a contacts and links module. As you can see, each module can also retain it's own container or if you wish you can turn off module containers within tabs which is the default.
You can insert a break after each module which puts the next module below it, or you can clear this option so the modules are displayed side by side. In this demo a break is inserted to start the links module underneath the contacts module.