By default we have a set of all major currencies implemented in our database which can be modifed or updated by admin 
To add edit or remove any of existing currencies just navigate to : admin panel login -> General -> Curreries 

Now from this page you can manage your currencies or setup any of these as a default system currency. 

To setup auto currency prices update you can see the CRONJOB url just copy it and add to your cpanel cronjob and setup the best time for update. we normally setup 1 visit for each 24 hours but you can setup according to your needs. 

Befure auto currencies prices works you need to signup with with
once you signup you need to copy your currency API key and edit file ( config -> currency.php ) located on root of your files 
remove the old key if exist and add your new key and save the file. 

That is all.