To start TTD with the patches enabled, simply run ttdpatch.exe. At the first start, it will copy the old executable to ttdload.ovl, patch it, and then run it. Additionally, it will create a configuration file if none exists already. These steps will be omitted after the first start.
You now need to have 9 MB of free memory to run TTD, because of the possibly larger number of vehicles. This is true even if you don't use the morevehicles switch. However, with the new lowmemory option, you can reduce this requirement to 4 MB, at the expense of not being able to have as many vehicles or new graphics.
If you are starting TTD from Windows 95, just change the shortcut command line to run ttdpatch.exe instead of tycoon.exe or ttdx.exe, and append any of the options you would like to have.
For the DOS version, you can pass any parameters to TTD, just add them at the end of the ttdpatch command line. This will in most cases be the path to the CD drive, if your TTD runs only with the CD in the drive.Example:
D:\Games\TTD> ttdpatch -av E:\will run ttdpatch will all switches enabled, and tell TTD to look for the CD in drive E:. For an explanation of all switches and options, please see Command Line. Alternatively, you can set the CDPath directive in the configuration file to point to your CD drive, with the line
in your ttdpatch.cfg file.