Hi and welcome in the forum.
![Smile :)](./images/smilies/icon_smile.gif)
For first thing, you can use the forum
search function to find in older tropic about what you're asking, and right in this section as annoucement, there's
this topic about a starting guide on how make a track for MM2. For first thing you need programs like
ZModeler and
MM2 City Toolkit, used to model the track and make it for MM2.
Here's a complete tutorial made by the MM2 City Toolkit program author always about how make a city for MM2.
The bound file of the PKGs is automatically created when you make the track with the MM2 City Toolkit program. Is so also when you export an object properly fixed as .pkg file with ZModeler.