Buy stablecoin sUSD
You will need stablecoin sUSD in order to buy "Crypto Large Cap TrendMax". From the top menu of Binance, Open Trade -> Classic, an order book trading platform with different pairs are shown.
The path to get sUSD is to swap your local currency to USDT, then swap USDT to sUSD. For example if your local currency is AUD, from right side of the webpage, enter AUD/USDT and click on it. At the bottom, enter the maximum amount of AUD you want to sell, choose Market order and click Sell AUD. When the transaction is executed successfully, you will have USDT.
Next is to swap USDT to sUSD. Similarly, enter SUSD/USDT at the right side in the pair list search and buy sUSD with all the USDT you got.