Area for managing payment systems used to bill your site members.First of all, you need to choose which currency will be used on the site.
You can either choose currency from the list of preinstalled or add a new one.

To enable a certain currency, click ‘green circle’ icon against necessary currency.To edit currency, click ‘pencil’ icon, to remove it – click ‘cross’ icon.
To add new currency, click corresponding link and fill in the form for new currency creation.
After you choose currency for your website, you may want to setup format for displaying cost.

Multiple currency feature recalculates prices within site listings. Paid membership, paid services, advertising opportunities’ fees aren’t re-calculated. It’s connected with the fact that when paying a site member will have to pay in 1 currency – the one that is set up by default in a payment gateway account.
Note: Set up admin_cron_currency_rates.php cron file on your server to enable multiple currency convertion. Currencies’ rates are provided by

Payment systems settings
You can choose one or a few payment systems to be activated on your website to bill your customers.
Click payment system icon to activate/deactivate a payment system or enter its settings. 
Fill in payment system credentials and put a tick against ‘Make this payment system active’ to activate it.