Using this Perrin coolant overflow tank is easy. First, follow the included installation guide to install it in your 2015 - 2021 Subaru WRX. It will take about an hour. Make sure to use the provided 3 - foot 5/16 - inch silicone hose and all the necessary mounting hardware. When using, keep an eye on the coolant level in the tank regularly. If it gets too low, add coolant in time. For maintenance, clean the tank every few months with a mild cleaner to keep it in good condition. Remember, this tank comes with a 5 - year manufacturer warranty, so if you have any problems, contact the manufacturer for support.