Ragnarok Online 2 (RO2) How To Get +8 / +10 / +15 Immediate Refinement Stones

The bound one (usually +17) are from Chenny's Snowflake, Chenny's Soul or Chenny Sunshine. This video is about the TRADABLE one, +8, +10 or +15.
Watch the video till the end to understand how to access this room.