The Keezel has 2 USB ports: 1 micro-USB port and 1 normal USB port.
The micro-USB port is for charging your Keezel - you can use the USB cable you received in your Keezel package to connect your Keezel to a USB port on your computer and charge it this way or you can use a regular, 1A phone charger to plug your Keezel into an outlet.
The normal USB port can be used to charge your phone or tablet with the Keezel. You simply have to connect the two devices with a USB cable for that.
The normal port can also be used to plug in a UTP to ethernet adapter into your Keezel so that you'll be able to use the device with a wired internet connection like the ones you usually find in hotel or conference rooms.