Well, @orinoco has a very simple system, and you're right, the guidance is realized in Discord. They are very active there. It is important to go there from time to time, to know if they're available, which banks they're using and things like that.

It's very easy to exchange. In the main page you select the trading pair, enter the amount and click on "Cambiar":

In the next option you select the bank account the money will be sent to, and click on "Siguiente":

Then you enter the Steem account that you will use to send the money, and click on "Confirmar":

Finally you'll see all the data you must use to send properly the money, always to @orinoco and always with the unique Memo ID of your specific bank account (every bank account receives a unique Memo ID).

There you will see buttons to fulfill the transaction at Steemit or SteemConnect, but I would advice always to simply copy the data into your Steem Keychain extension (in your browser), because that implies more security (signing every transaction locally, in your device).

Carefully control that your unique memo is correct and send the money. In next transactions you won't need to repeat this process... you can just send any amount of Steem to @orinoco with the unique Memo ID of your bank account, and the transaction will appear immediately in the waiting list.

If you're buying the internal token of Orinoco (Nectar) the transaction will be fulfilled immediately at any time. But if you're buying VES, it will be fulfilled in the working hours of the Orinoco team. You should go to Discord to stay always informed.