Mount the supply reel on the left mounting spindle of the reel-to-reel cassette deck. The supply reel will mount only one way, so flip it around rather than forcing it if it will not mount easily on the spindle. The take-up reel should already be mounted on the right mounting spindle of the cassette deck.
Thread the tape through the tape guards and past the "Erase," "Record" and "Playback" heads.
Thread the tape through the capstan and pinch rollers. Fold the end of the tape over, and slot it into the take-up reel slot from the right side.
Wind the tape onto the take-up reel counterclockwise a few times.
Push "Stop" and then "Play" to ensure that the capstan and pinch rollers will take up the tape smoothly and will not snap it.