Start with the benchwork
Add a table, then drag it into place. Tables snap to each other and to the grid.
Start with the room
Enter the room's size, then add doors, stairs, the furnace and anything else the layout has to work around. Or skip ahead to the tables.
Add some scenery
Draw a mountain by clicking its corners, any shape you like. Track underneath it becomes a tunnel, and the 3D view shows the real hills.
Lay some track
Pick pieces from the library and they join end to end. Or draw flex track, or start from an oval.