To cook baby porridge. if u're using 1 cup to measure rice.Add 3-4 cups of water. Depends on which veggies u want to add.Spinach,is one of it,lots of calcium.Protein,either fish or chicken. Blend ur prefered vegetables.Chicken or fish,cut it into small pieces(put inside pot.Alternative for salt is anchovies powder.(u can buy it online.) Slow cooker normally is use to cook meat.(to make it tender) Can buy a baby thermal cooker.It'll be much more easier.My elder sis,bought a thermal,only use it a few times.Because as ur child grow,he/she will start eating solid food.
I think some cookers comes with preset timings (not sure about the brands). I used slow cooker with auto (so no high no low) and it usually takes 1-2 hours (3 hours for my desired consistency). After baby turns one, I use rice cooker.