For all currency bets, you simply 'buy' if you think the first-named currency in the quoted pair is going to strengthen, and you 'sell' if you think the first-named currency is going to weaken.
If you are looking to take a short-term view, bet on the Spot price. All Spot prices have extremely narrow spreads, and bets settle at 8pm the same day. If you want to take a longer-term view choose a Forward quarter month in a currency. Your position will remain open until the last dealing day of the contract month.
You must also decide how much you want to bet per point. For all currency bets a point, or a pip, is the last full digit of the quote.
Trade on currencies now at IGIndex