To layer different perfumes you may like to spray the perfumes either over the top of one another or choose a different pulse point (neck, wrists, behind ear) for each fragrance.
Another method to layering different scents is to mix different mediums of fragrance. For example, Fragonard offers many of their fragrances in a range of products such as lotions, hand creams, soaps and gels. This is a perfect way to enhance any scent you own in a unique and subtle way if layering the perfume itself seems daunting.