Hi Trungtran!
Every skill by it self will have a basic strength. When you can pull up certain combination and rotation your will be able to get greater effects. 38 Abilities will take some time to understand and learn but we will make sure that even without understanding of every combination and detail you will have some cool effects! Every fight you will start with a small number of skills, and unlock new skills every round. So you evolve constantly and have time to learn the game just by playing it.
After all this is a survival game and learning the mechanics is going to be the fun part. The better you understand the possibilities the further you will get!