This isn't my field but in my experience, the best thing to do is closely watch the website. It appears that they released their call for papers recently. I would assume that all information on submissions would be contained there. It is likely that the submission site just hasn't opened. At a glance, it doesn't seem like you can register yet either.
In your shoes, I would just keep an eye on the website and wait for the submission/registration pages to pop up. Any fees you may have to pay will be obvious when you go to submit. If you need that info ahead of time, they will probably be close to last year's website prices.
...would the fees still be necessary even if the paper is rejected?
I don't see a deadline yet, but usually there is enough time to see if your paper is accepted before registering. You can look at last year's deadlines. Conference dates usually don't vary too much year to year. If you register before you receive a decision, then you're locked into whatever cancelation policy they offer. There should not be a significant separate submission fee.