Formula Help!

FTM and I will be formula feeding (don’t want to get into why/have debates). I have no clue when to buy the formula, what to get, and how many? Can I buy some formula now? Can I use infant instant formula bottle packs at first or use them at night only? I’m due March 1st. I’m really clueless when it comes to formula. I’m not looking for judgement or for someone to force me into breastfeeding. Just looking for help from one mama to another. Thank you!