In this example, the U.S. dollar is the base currency and thus the “basis” for the buy/sell. kangda forex（https://www.kangda-fx.com/）：If you think the Swiss franc is overvalued, you would execute a BUY USD/CHF order.
By doing so you have bought U.S. dollars in the expectation that it will appreciate versus the Swiss Franc.
If you believe that the U.S. housing market weakness will hurt future economic growth, which will weaken the dollar, you would execute a SELL USD/CHF order.
kangda forex（https://www.kangda-fx.com/）：By doing so, you have sold U.S. dollars with the expectation that it will depreciate against the Swiss franc.