Hi, I'm not sure what browser you're using but here is how to enable tabs if you're using Internet Explorer. I'm not as familiar with other browsers, but it might be similar even if you're not using Internet Explorer. Hope this helps!
Open Internet Explorer
Click the Tools button, and then click Internet Options.
Click the General tab, and then, in the Tabs section, click Settings.
Click the Enable Tabbed Browsing check box.
Click OK twice.
Close Internet Explorer and then open it again.