Talk to the NPC here and he will send you on a quest to find trunks

Becoming an Archer: Now that your job level 10, it is time to go to the archer village. Go back to Payon, and the archer village is the portal in the north-east section of Payon. Once you’re on the archer village kaos war gold map, go to the north-east side and you will find the archer building. 

Obviously, this is where you will become an archer at. Talk to the NPC here and he will send you on a quest to find trunks. Just find 25 trunks of any kind dropped by willows. 

You have to get up to 25 points to become an archer. If you get more than 25 pts, you get some free arrows as well as the bow you get. Not too shabby, I must say myself. 

Anyways, it shouldn't take too long together enough trunks and to reach 25+ pts. When you finally get enough trunks, return to the Archer NPC. Talk to him and he will transform you. 

Congratulations, you are now an archer! Now it's time to level up your newly acquired archer. But where?

If not, stick with the basic level up areas and that way you actually make money and you also level up at a decent speed. Also, cliff sniping can be dangerous so make sure to watch your back.