I've made a video tutorial for joining two tracks: http://cream.galleria.fi/Shares/LINKED/merge.7z (230MB) (Link provided by Kennett Ylitalo, see here for full story) To extract the files, you'll need to install 7zip, which is free. Extraction may take a while since the compression ratio is as high as the format allows. In the videos, I go through my way of merging tracks, while explaining what I'm doing and why. If you want to practice but you don't have 3dSimed, you can use the demo version, but bear in mind that the demo version can only export a small number of objects. That should be fine if you just want to practice merging tracks in a new project that doesn't have many things in it.