Also, if you go from LTC/BTC and you want to buy NEO, do you sell to USD and then buy NEO/BTC.
This cross crypto is confusing. Any help would be thankful
in an exchange there is a usdt, that is an equivalent of usd. Its value is fix so if you want to make a short trade, you can convert it to usdt. You can all see it in an exchange website, a pair of coin trade, example is btc/bch or btc/eth trading.