Step 1: Supplies

At least one container of crayons depending on canvas size
Canvas
Hair dryer or heat gun
Newspaper
School glue
Your imagination

Step 2: First

Put your news papers down under your canvas to prevent spillage then arrange and glue the crayons in the place of your choice

Step 3: Second and Last

Use to heat gun or hairdryer to melt the crayons and watch the streams of vibrant colors flourish on the canvas until the your done

Ps found the most controllable technique is to have low air speed lay it flat and tilt your canvas to control the melting crayon rivers