In this Example of a Limit Order, we are buying 0.001 BTC at $41,573.4, essentially taking an order which is already in the market, as shown in the order book on the left of the screenshot. In the trade ticket, the top field labelled ‘USD’ is where the desired order price is entered, the field labelled ‘BTC’ is where trade size/quantity of BTC is entered, and the ‘USD’ field below (optional) is only used if we want to specify the size of the trade in USD instead of BTC. If we input a value into the lower USD field, the platform will convert said value to BTC and populate the BTC field automatically. Inversely, if you populate the BTC field, the system will auto-populate the USD field.