Your free trial of Inspect expires after 30 days, and you will be notified beforehand, so you can choose to either enter your payment details or cancel.
It's early days for Inspect, so the early builds might have bugs and issues, but please report them using the issue reporter from inside the app.
Inspect is using the iOS driver provided by Apple, so you need download and install iTunes for Windows.
Once installed, start iTunes and pair your phone so iTunes can sync the device.
Now Inspect should be able to see your device.