Price makes a steep move higher, often in a straight-line run, leading to the first peak.
The height from the launch price to the first peak should extensive, often twice as tall as the distance from the first peak to the bottom of the valley between the two peaks
Two peaks top out near the same price but allow variation. The average price difference between the two peaks is about 1%
When price closes below the lowest valley between the two peaks, a breakout occurs and you have a valid big. If, instead of breaking out downward, price first closes above the highest peak, then you do don’t have a big M.
The chart pattern should look like M once it completes