There is no specific method mentioned in the Quran and Hadith for applying attar. Therefore, whichever way you apply attar, inshaAllah, the Sunnah of applying attar will be fulfilled and you will receive its reward. However, since the Prophet (peace be upon him) preferred to initiate good deeds from the right side, it is also Sunnah to start activities related to cleanliness, grooming, and adornment from the right side. The method of applying attar that is narrated from our pious elders (who were devoted followers of the Sunnah) is that they used to apply the attar to their palms first, then rub both palms together, apply it first to the right armpit, then the left armpit, and then on the shoulders and chest. In this way by starting from the right side, the Sunnah of initiating a good deed from the right side as well as the Sunnah of applying attar will be fulfilled.