To clean my tanks I just use plain white vinegar. It does a great job of getting out hard water stains, and dried on algae. Do NOT use any soap. Make sure to rinse well in hot water, and when you think it's rinsed enough rinse 2 or 3 more times, and you should be good to go.
I'd set it up and let it run a day or 2 without any fish to make sure the seals and equipment are all good. You might want to so a water tightness test for 24 hours before setting it up at all