Follow the instructions manual provided by the pack.
Insert a new cartridge into the pen by pulling off the cap and unscrewing the cartridge holder from the body. Then, insert the new cartridge into the holder, narrow end first. Screw the cartridge holder onto the pen body until you hear a click sound.
Check your insulin before every injection and attach a new needle for each use.
Select the dose and inject the dose.
After use, remove the needle and discard it.