You need to understand ETN is currently already very low you can not think of any PROFITS out of ETN/BTC pair, while BTC is sitting above 8K ,
The only way of having ETN in cryptopia and making profit is by selling your ETN which you have mined or selling it with some other Alts.
I would suggest you to hold on to your ETN and let the price increase.
And by how its very simple you click on your desired currency pair ,let say ETN/BTC , so if you want to sell ETN you see the "Sell ETN" option simple