Tethering is a simple concept. You would have a computer that needs a connection to the internet. If you are into the Apple Ecosystem with an iPhone, and a Mac Computer, then you simply select your device to connect to. This will show as an option when you don’t have a wifi connection. If you don’t have this seamless example, the cellular phone can be setup with an SSID?, and password. You would turn tethering on your device, and the computer should see the SSID as an option. You select the SSID, and enter the password. Once that happens, you would be able to use your device as a modem, and do whatever you would need to do. There is no data cap, but you are limited to the speed you paid for.