You can go to https://coinmarketcap.com/currencies/harmony/markets/ and choose whatever exchanger you want.
But I will explain how I bought ONE in Huobi Global.
Go to https://www.huobi.com/ and register if you don’t have the account. Go to spot trading and Type ONE, you get 3 pairs. I used USDT. You need at least 5 USDT to trade. It’s cheap.
After you bought it, go to your account and find ONE and click withdraw.
You will need a one1xxxx address. You can read it here on how to generate one1xxx address from your ETH address (https://medium.com/@blockhainzpringles/how-to-generate-one-address-from-metamask-f25be5e48a13)
After you pasted your one1xxx address, input the amount you want to send. After you send it, it will appear on your metamask. Don’t forget to change into Harmony mainnet.
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