Rake the gravel pad where you'll be installing the hot tub to ensure that the gravel is level and free of any debris.
Place the hot tub in the desired location and make the necessary electrical connections. You may need to hire a qualified electrician to do this.
Clean the hot tub of any debris or dirt with water and a mild cleaning solution. Check the manufacturer's recommendations for specific cleaning agents. Tighten all water pump fittings by hand and tighten the drain valve.
Fill the hot tub from your hose to a level 2 inches above the filter intakes. Turn on the hot tub and then activate any jet nozzles on the tub. After they've run, shut off all the jets and set the tub temperature. Let the tub heat to the desired temperature. This may take up to 24 hours.
Treat the water with a hot tub water treatment kit. These are available at pool supply and hot tub and spa shops. Follow the instructions on the kit for the proper water treatment.