When to feed baby rice/oatmeal cereal?

Question

How to introduce it. How often, what age ect.. please tell me everything I need to know!! Thank you so much.

Answer

Ideally you want to wait until baby is 6 months old and sitting independently before offering anything other than breastmilk/formula. 
Some baby’s can handle “solids” a bit earlier than that, but there’s now way to know for sure unless you look inside their stomach with a microscope to see if their digestive system has matured. Since that’s not really an option, waiting 6 months is safest. 
Infant cereal is never necessary. It’s over processed and has little to no nutritional value. Additionally, rice cereal in particular contains naturally occurring higher levels of arsenic which is concerning, especially for little babies. 
IF you do choose to feed infant cereal, always do so with a spoon, prepared following the package instructions. Never add it to baby’s bottle as that becomes a choking hazard. 
Of course it’s always best to speak with your baby’s pediatrician about what is best for YOUR child, but if your ped suggest starting solids before 6 months, I suggest you question WHY they think you baby is ready. What specifically about your child makes them think he/she is ready before the current recommendation of 6 months? (Many pediatricians it seems simply aren’t up to date and still operating by outdated guidelines). 
Also, here’s an infographic that better explains why infant cereal isn’t the best nutritional choice, and some other “first food” ideas.

Answer

Our pediatrician gave us the go ahead at 4 months. He was showing signs of readiness. Sits well assisted. Watches us eat, smacks his lips. He also has been puking a lot since we came home from the hospital and thought maybe oatmeal would help keep things down. We do just oatmeal mixed with breast milk or formula. Started out with just a tablespoon and very runny. Upping the amount and consistency as he got better. I’ll slowly add more oatmeal at other mealtimes. And when he gets closer to 6 months I’ll start purées and tablefood. Not every baby falls within the 6 months guideline but make sure talk with your pediatrician 👍🏻

Answer

6 months at least, I would do your own research and decide what food you want to start with and how often to serve it, everyone does it different.