Mix maida, salt, oil together and knead it make a dough.
Make 20 small balls out of this dough and with the help of rolling pin roll it like a thin chapati.
Mashed potatoes and green peas keep it separately. mix chopped onion,green chillies, red chilli powder,coriander leaves,salt and divide it into two portions. one portion mix with mashed potatoes and the other with mashed green peas.
Now take one chappati over it spread the mashed potatoes,place another chapati over this and spread mashed green peas and over it join with another thin chapati.
With the help of water join all three chapatis round ends together.