The amounts on the recipe are a rough suggestion. No need to adhere to them strictly.
Some green mangoes are not very sour. So you may need to add more lime juice. conversely, very sour green mango may not need lime juice. But lime juice goes so well with fish sauce.
Peel half of green mango and leave the other half unpeeled for an easy grip while shredding. Shred the green mango with a shredder.
Slice chili peppers into thin slices. Peel and slice a shallot.
Add everything into a dipping bowl. Pour fish sauce on top. Squeeze the lime in. Top the sauce with sliced chili peppers.
Serve as a condiment with Thai food.