To perform the Rainbow Road shortcut in Mario Kart 64, follow these detailed steps:

### Step-by-Step Instructions for the Rainbow Road Shortcut in Mario Kart 64

1. **Starting Position**:
– Begin the lap by driving on the right side of the track.

2. **Identify the Green Tiles**:
– After the finish line, count the green tiles on the right side of the track. The shortcut involves turning left at about the third green tile.

3. **Turn and Hop**:
– As you approach the third green tile, turn sharply to the left.
– Immediately after turning, hop over the railing on the left side of the track.

4. **Clearing the Railing**:
– Aim for the spot where the railing meets the track, and time your hop perfectly to clear it.
– You should land on the loop going around the large star.

5. **Landing Position**:
– After clearing the railing, you will land on a section of track below, skipping a large portion of the original course.
– Be cautious of Chomps that may appear in this section.

6. **Practice Timing**:
– To master this shortcut, practice in Time Trial mode. The timing of your hop is crucial to successfully executing the shortcut.

### Additional Tips

– **Alternative Shortcut**:
– There is an alternative harder shortcut that can be used to save about 9 more seconds. This involves driving to the left side of the road, turning right at about the second orange tile after the finish line, and then performing a left-facing slide close to the fence on the right. At the third green tile after the finish line, push the control stick all the way to the left and brake to help turn more sharply. Hop at the left edge of the road to go over the star fence and land just before the end of the spiral.

By following these steps and practicing your timing, you can successfully execute the Rainbow Road shortcut in Mario Kart 64 and gain a significant advantage in your races.