Navigate to the folder where Train Driver 2 is installed, then navigate to \Launcher\TD2\2022.1.1\TrainDriver2\td2-game-package and copy the contents of the folder into the \[username]\Documents\TTSK\TrainDriver2.
Just be aware, as the "TTSK" folder inside Documents may be hidden or marked as a system folder, so don't be scared if you haven't found it that easily.
And - just in case - prior copy the contents of \td2-game-package\ to the separate folder as a backup