Now that you have completed the first leg of the quest, look for the NPC named Lenphad in Elder Village. Lenphad is the Equipment NPC for this map and can be found at the top-right level of the village, just next to Echo the Alchemist. Talk to him regarding the class-advancement quest, and he will give you a set of tasks to complete. The advancement quest for Sniping Ranger has three parts but all can be done in Wally's Castle.  If you haven't unlock Wally's Castle yet, make sure you complete the Suburbs of Wally's Castle first in order for this map to be available in your dungeon selection. You must clear this dungeon with a rank B or higher; otherwise, you will have to do reruns. There is no time limit for this. They can be found on any floor of the dungeon, so make sure you have explored the entire area.  Don't forget to collect High Quality Lubricants from the Crossbow Soldiers (you will need 2), as these are quest items. If you ever got disconnected from the game while you're in the dungeon, the monster kill, including the number of quest item you collected will remain. However, your stamina will still be deducted. Mini bosses will be available in this map; killing them will give you a chance of obtaining rare items, which can be useful for your survival. Once you have completed the quest, return to the Elder Village and open your Quest Log by pressing Q. Click the first-class advancement quest and then press Complete. This will complete the quest for the class change and will automatically turn your Rena to Sniping Ranger. If ever your character didn't change \to Sniping Ranger after completing the quest, simply log off from the game and then log in again. Sometimes the server is too busy to register that your class has been updated.
Look for Lenphad. Enter Wally's Castle under Very Hard mode. Kill 12 Crossbow Soldiers while you're in Wally's Castle. Return to Elder Village.