There are two basic types of electrical circuits; series and parallel. A complex circuit can consist of sub circuits of each kind.
Step 1: Series Circuit
In a series circuit, the path of electrons from the negative (-) side to the positive (+) side goes through all the electrical components of the circuit. Another way to think of this is that if you open the circuit at one point, on either side of a component, there is no complete path for the electrons to follow from - to + for any of the components. A good example of this for those of you old enough to remember is the old style Christmas lights where if one light were to burn out, the whole series of lights would go out. Series circuits are used extensively in electronics but rarely by someone who is providing power to electrical components such as supplying power to a group of lights as in the case of low voltage LED lights sold by Berkeley Point. A simple schematic of a series circuit containing three electrical components (represented as light bulbs below - icky incandescent light bulbs at that), is illustrated below:
Step 2: Parallel Circuit
In a parallel circuit, each component has its own direct path to both the negative (-) and positive (+) sides of the circuit. A simple schematic of a parallel circuit is shown below. In actually wiring the LED lights from Berkeley Point, as long as the red leads from the lights are connected to a wire that goes directly to the positive (+) side of the power supply and the black leads are connected to a wire that goes directly to the negative (-) side, you have wired the lights in parallel. If you follow the wire path back from a light to the power supply, it can "T" to other lights but should not go through any other lights. If your feed wire is similar to the Belden wires provided by Berkeley Point in so far as they consist of a red and black wire. In a parallel circuit, you will never have a black wire connected to a red wire (contrasted with example of series circuit shown above). Further, as long as you can follow a path from the red wire of a light back to the positive (+) side of the power supply through red wires and the same through black to the negative (-) side, you have wired in parallel. A group of many lights may have all their red leads connected together with one red (+) feed wire and all their black leads connected together with one black (-) feed wire.