Installing "official" add-ons into early versions of Trainz including TS12 (pre-SP1):
Note: This guide is for items that have a downloadable "installer" setup file in SimulatorCentral. TANE use a new system for DLC.
1. Double-click on the Installer
2. Choose Run
Note 1: ignore the warning "the publisher could not be verified"
Note 2: If the setup file is not recognised, right-click the file and then select 'Rename' then add '.exe' to the filename.
3. "Allow the program to make changes" - select Yes.
4. Installer will run through several steps. Enter your serial number when prompted. (Your Serial Number is found in your SimulatorCentral account under "My Downloads")
5. Choose the install path to match your TS12 installation directory
6. Once the installer is complete, Launch Trainz
7. From the Launcher, click on Options to check your add-on serial number is showing under your TS12 serial number.
If not, you have most likely installed into a different directory.
8. Start Trainz (it will check your asset database) and choose your favourite route, and Edit Route or Edit Session.
9. In Surveyor, open the Trains Tab, click on the "Train Mode" icon, and scroll down the list to see your new add-on train set.
10. Place the train onto a piece of track, then click QuickDrive.
11. You can also use the search filter to find more related items. e.g. for Coronation Scot, type in LMS then open the Trainz Tab > Vehicle icon to see a list of all LMS rolling stock.