Castaways, SE not for a beginner.
As a 'wave beginner' Possibly the easiest ocean/wave spot on the coast is (SE Winds) is 'Neil St' Caloundra, this is where you will find most people wave sailing, once you nail Neil St and get to the next level, try Peregian or Coolum in SE...Castaways/Sunrise/Sunshine SE is too onshore, Ok if its Sth, all of these are hard core places, full on sweep and dumping waves....Neil St is pretty user friendly, easy to get out.
Others might say 'happy valley' is the easiest...can be.. but it quite literally has a killer tide that you need to be on guard for.
When you get good there is a couple of special spots at Coolum, but you need to be in 'just the right spot' to nail them, otherwise it's swim city and trashed gear!