Welcome. First tell us what country you are in. Next, get rid of that stone!!!! next, if you can, plant it in the ground for a few years. Why? Because it is just a seedling and needs to grow. Styling will come in time, right now it has to grow a whole lot more. There is nothing else you can do to it other than add fertiliser every couple of weeks, until your late summer. Use a low nitrogen one. Don't do any pruning until the late summer.
Geoff