Baby formulas that are meant to be used from birth, or to replace or supplement breastmilk, come in two types. The ones that are whey based, will be promoted as 'closest to breastmilk.' Curd based formulas will have 'for hungry formula fed babies', written on the tin. This is because curds take longer for a baby to digest. It also makes them 'less close to breastmilk ' than whey based formulas, but you will never see that written on the tin.
Whatever your reason for using formula, it is better to start with a whey based one. Follow the instructions, exactly as they say on the tin.