It is presumed that you wish to make an isolated block for a dead end siding. The block track goes anywhere you want to start the block. To power the block, one wire from the switch goes to the transformer track power terminal that goes to the center rail of your layout, and the other wire goes to the isolated center rail of the block track where you removed the wire. Transformer power is applied to, and removed from the block through the switch.
If you are creating a block such as is shown in the block track instructions, then you need 2 block tracks. Wiring depends on exactly what you are trying to accomplish.
Larry
