Two Methods
Leonel did really want to enter the Archery Faction to see what they had to offer. Mostly, he wanted to see what the highest echelon of bowmen in the Human Domain could do.
Although it was a bit embarrassing now that he thought about it, Leonel's greatest reference for top tier archery until now was from the "genius" of a family small even in comparison to the Luxnix. It was he who taught Leonel that Bow Force could be used cleverly to change the direction of an arrow mid-flight.
Outside of this, Leonel had been on his own. This just went to show the sheer amount of talent Leonel had in the bow. Even seemingly without much effort, Leonel had been able to form Enlightened Bow Force. In fact, now, after applying his grandfather's path of the spear to his bow as well, the current level of his Bow Force was on a level most couldn't fathom.