For AT&, tethering is only available on the 5GB 50.00 data plan or the mobile share plan, unless you have one of those you cannot tether.
Tethering capability should kick in within a few hours to 24 hours on your iPhone 5s or AT&T smartphone. If it doesn’t then you will have to contact AT&T tech support.
Now that more and more people have started using smartphones, AT&T and other carriers are not Unlimited in data as they once were. For more info on iPhone wireless and USB tethering visit http://www.jailbreakmodo.com/unlimited-3g-tethering-on-usb-and-wifi-mywi-jailbreak-app.html