A future is just an arrangement to exchange gold at terms (i.e. sums and costs) chose now, yet with a settlement day later on. That implies you don't need to pay up right now (in any event not in full) and the merchant doesn't have to convey you any gold at this time either. It's as simple as that.
The settlement day is the day when the genuine trade happens - i.e. at the point when the purchaser pays, and the dealer conveys the gold. It's normally up to 3 months ahead.
The gold trading is very profitable trading, by that you can earn lots of profit.
