How to get the alloy equipment 5 phantom pain butterfly medal

We already know that if you want to keep the silence in "Metal Gear 5: Phantom Pain", you must get the butterfly medal as soon as possible. Then the question comes. How does the Butterfly Medal in "Metal Gear 5: Phantom Pain" get? Many players don't know much about this. Don't be impatient. The following system is a series of tips and tricks for you to share with you. I hope everyone can enjoy it.
The way to get the medal of the butterfly is to carry out the three main line missions quietly. The quests must be yellow, and then the number of enemies is more than BB. You must have the evaluation completed.