Hi there 71ange,
It's vital that all your transactions be entered properly for your books to be well balanced. QuickBooks Desktop is a great tool able to help you keep track of money in your accounts to see the financials of your company. I can point you in the right direction to enter your transactions.
In order to affect another currency than your home currency in a General journal entry, you'd need to select US dollar from the Currency dropdown. Afterward, you'd need to choose the accounts you'd like to affect in the lines, as well as if you want to apply a tax rate, then enter the balance of the line in credit or debit, with that amount being in the foreign currency. The next step would be to adjust the exchange rate so that the amount in a foreign currency will be the right value in the home currency once the transfer is complete. Once your credits and debits are matched, you can save. If the transaction is of the right amount but is in fact increasing the account balance you should be increasing, you'd need to return and change the dits and credits for each line.
If you have any other questions, feel free to reach out here