Several options can be set. Most of them don't need any explanation.

When you start Tyre the first time, the options window will be opened. Set the options carefully according to your own preferences.

Connecting TomTom itinerary files (*.itn) and TomTom POI files (*.ov2) to Tyre is not necessary, but it is most helpful: your itinerary files and your files with Points Of Interest will be opened in Tyre, just by double clicking on those files.
If you uncheck this option, you can only open those files if you run Tyre first and than choose 'Open...' from the 'File' menu (or by clicking the 'Open' speedbutton).

If you don't want to wait for the weekly check for updates (or if you unchecked that option), you can check if you are still using the most current version of Tyre by clicking the 'Check for update now...' button.

If you encouter problems on running Google Earth, you might reconnect the appropriate files to Google Earth. This can be done by the 'Google Earth' tab.
To learn more, click here.