Before using either the platforms or zipline, you must first activate the power. After that, you must unlock the area that the platform or zipline ends at, otherwise it will not take you anywhere. The zipline can be used if there is no notice saying "Closed set" (indicating that you must unlock it) or "Power must be on" (power needs to be turned on). Once the zipline is active, jump into it near the edge. The springing platform can be used once the area (lighthouse base) is open and the power is activated. When you stand on it, you will hear a compression sound. Then, after a moment, it will launch you away. Beware as zombies and George can also use them.