How to enable your On Demand service for the day.
Make sure you are connected to the Insty Wifi network.
Log in to the Insty Dashboard at http://192.168.8.1/quick.html

Click on the Modem Dashboard to bring you to the cellular portion. From the Modem Dashboard, you'll want to check that you are connected to the network by looking at the signal and the network name. If it says "T-Mobile" or "Standby" or "INSTYCONNECT" you will be able to enable for the day, if it says "No Service, or Searching", that means you are outside a T-Mobile area and will not be able to enable the service.

Click the "Enable Now" button next to the "On Demand Internet". It will then send you a 6 digit code to verify:

Click Verify and Enable.
It should then show an activation message. Give it about a minute to switch into live mode. When it's active, it will say "On Demand Active".