Here, you can learn about how add Exchange Rate.
1.Login with Fresa Gold, Open Accounts-> Accounts-settings -> Exchange Rate (Fig.1)
2. You can create the Exchange rate for your User rights currency only. Now you can see your user currency list.(Fig.2)
3.You can get the list of Exchange Rates, Click create button.(Fig.3)
4.Select Effective from date, from currency, To currency and Enter the Sale and Cost amount then Save.(Fig-4)
Hope you got an idea to add exchange rate.