A detail I forgot to mention is about the API Secret Key input field in the setting page. Not sure why the developer decided to add it, coinos does not provide it anyway, so you can just use a random generated one of your choice. Don't bother sending a request to coinos support from the link provided, again, you'll not get it via coinos team.
Another minor detail of this plugin is that you can check your coinos balance straight from the WP admin > BTC wallet ... too easy!