1. First, open your online banking application and log in to your account. Then, click "foreign exchange" or "overseas remittance" or similar options. Next, on the transfer page, you need to fill in some necessary information.

2. Select the currency to be purchased, that is, Japanese yen, and fill in the details such as the amount to be converted and the exchange rate. After selecting the appropriate option, you need to enter some payment method information. You need to make sure that there is enough balance in your account to exchange the corresponding currency. At the same time, you may need to provide some identification, such as mobile phone number and ID number, to ensure the security and legality of the transaction.

3. Finally, confirm your trading information and submit it. If the transaction information is correct, you will successfully purchase the corresponding cash yen.