You are totally right, we are missing an ingame tutorial, we added a video to the game page of how to catch a jellyfish to explain the mechanics you can see it here
thanks for all your feedback is not discoraging at all, I think the most important thing missing for us was a good tutorial and more variety of creatures, the catching minigames are the things that breaks the etherna boredome of just swimming around, we plan to keep working on the game adding content and more mechanics, thanks a lot for all the feedback is really appreciated!