How to make a bottle !

FarmWife 🌾 • 2015 👧🏼 2017 👼🏼👼🏼 2018 👧🏼 🌈 2020 👶🏼
Ok, maybe a silly question and I realize instructions are on the back of formula containers. But how do you make a bottle ? What is the fridge life and the time it can sit out of the fridge ect. I was an exclusive breastfeeding mother and the time has come that my supply is so low I need to switch. Formula smells so sour all the time!! I hate to even feed her it!