You should have:
The tape machine
The sprocket that holds the tape
A roll of 3/8" tape with a 3" core
Insert the sprocket into the core of the tape roll
Drop the tape loaded onto the sprocket in the slot at the rear of the machine
Stretch the tape over and a little past the top of the front slot.
Make sure the sticky side of the tape is facing up
Thats all there is to it, you are now ready to begin sealing your ground meat bags!