HP Color LaserJet CP6015 Printer series - Manual (Page 179)

2. Push up to on the staple cartridge to remove it from the booklet maker or stapler/stacker.
3. Insert the replacement staple cartridge unit into the stapler unit.
4. Push the staple cartridge unit into the stapler unit until it clicks into position.
5. Close the front door.
ENWW Replace supplies 165