Ill throw in my thoughts. There are two main ways to use it, you can either put it into the tank or introduce it into the intake system via a vacuum line. Ill be the first to warn any one with a plastic intake, that adding any cleaner via a vacuum line can be super dangerous. There is a nice gouge out of the wall at my shop due to this.
Tank method: Read the directions but I think it says to add to a full tank or at so many gallons. This will run through anything fuel does. The main benefit is at the injector end. It cleans your injectors from the inside and where the fuel exits the injectors, this is normally on an intake runner, combustion chamber and the backs of a valve or two.
Vacuum line method: With this, you are introducing very small yet even amounts of the liquid cleaner to a vacuum line. If done correctly you pretty much atomize the cleaner, cleaning anything that air and the air/fuel mixture touches. This will get the intake runners, the external TIP of the fuel injectors, combustion chamber and the backs of the intake valves. ** please note you can cause a lot of damage with this method to yourself and your engine** they key is to do it slow and easy. This should also cause a large plume of smoke!