First of all, we should know what "hand" means and how to do it. There are also several currencies most commonly used in foreign exchange (US dollar, Euro, Japanese yen, British pound, Swiss franc, Canadian dollar, New Zealand dollar and Australian dollar), which are also commonly used major currencies. In addition, we should know what is the benchmark currency, quotation currency, spread, floating spread, bid price, selling price, quotation contract, transaction cost, cross currency, margin, leverage and so on. These are all things that need to be understood and mastered. It can be said that these are the most basic things.