Hello
@DreadShi,
There are many many approaches to this, I suggest you to learn a little bit more about how TFS and OTClient works in order for you to decide which approach you feel like taking on.
Basically you have either the clients shader and draw, which might feel very advanced, perhaps too complicated if you have no experience with programming or you can just import the aura to the sprites file as an outfit over the standard outfits and add these new outfit IDs to the server so it knows which ones it can deliver to the player.
Let me know if you need further help or questions.
Best Wishes,
Okke