Below are links to two guides which will explain how to enable the multicurrency feature and create multicurrency bank accounts:
When creating transactions in a foreign currency, the system will always store the value of the currency you create them in and the converted value in your home currency. Multicurrency bank accounts will therefore always show the balance of the payments in the foreign currency and the converted value in your home currency.
Follow these steps to switch between your home currency and the foreign currency of the bank account on a bank statement.
Navigate Money > Bank accounts
Click on the name of your foreign bank account.
To switch between the home currency balance and the foreign currency balance hit the switch currency button to the right of the search filters highlighted in blue.