As far as I know, you are at the peak of testosterone production up until 25 y.o., that means that you can put on tons of muscle easier than an older male. So you have to research about training and proper nutrition, and first of all decide what you want to do; cut or bulk.
If you are more than 15%bf I would recommend you to cut for three months and after to bulk until you reach that bodyfat percentage. As it has been shown, you can get more muscle between 7-15% bf .
If you are already lean start bulking; count macros and tract calories and eat much more than maintenance. You will probably gain fat as well but at least you will make progress.
It's your decision, you choose whether you should lose or gain weight, it is not possible to do both as long as you are natural.