Instructables

Step 9: Lights - Spot Lights

The last one to add to the rail is the spot lights. Since these are pond lights, I couldn't cut any of the wire because we are planning on keeping them for when we need them. The wire ended up having to be coiled up neatly and it did have to be cut in one location, but only one wire. It will be an easy fix later. 
What you need
Some sort of spot light

Step 1: For me, nothing had to be done, but normally you would wire the inputs in parallel.
Step 2: Glue the lights onto the rail. This is important if you want to aim the lights: The lights only pivot forward or back, so the one in the middle should be perpendicular to the rail. The two other lights should be at an angle perpendicular to the rail. See picture 2. 
Step 3: Continue the wire to the end of the rail
Step 4: Continue on later