No BM and Collostrum 3 days postpartum

Hi Mummies, Im 3 days postpartum (c-sect) and have been encourage to breastfeed my baby even thou nothing is out to stimulate the breast, after 15 minutes latching will then feed with formula. How to know if I will have milk supply coming in later? My nipples are as well 😭 There isnt any colostrum as well to collect. #pleasehelp #firstmom