Hey there,

Head into 'Account' at the top of the page and select 'account balances'. Then it should bring up a table with all the currencies - find the currency you want to deposit and on the right hand side of the table you should see an 'X actions' tab. Click on Deposit/Autosell and it'll bring up a dialogue box. Generate a new address and then send your coins to that address. As a precaution, I always send a small amount first to make sure it goes in properly. It may take a small while for the account to register a transaction so don't freak out if it immediately doesn't show up in the 'pending transactions' box.

That should do it!