S.H.
The best is to ask your Pediatrician, since he/she would know your baby best and any specifics.
the reason to offer 1 food at a time, for at least 1 week at a time, is to rule out any adverse or allergic reactions.
Every new food you introduce, keep it separate at first. Do not give any meats yet (baby food), it's too early and baby digestive system & kidneys cannot process this yet.
Build up slowly... solids at 1 meal per day. Then, gradually, (some say after several weeks or after a month), perhaps add 1 other meal. Then over time, before you know it, baby will have 3 meals of solids a day.
Usually, do an "orange" or "green" type vegetable first....then, at about 12 months (per my pediatrician) meats can be added. Later, tofu is also a great "vegetable" based protein. Also, do not give spinach yet....even baby food...for at least I think it was until 9 or 12 months old...there are certain things in it which is not good yet for a young baby.
Everyone is different...but my pediatrician prefers to add different food groups slowly and over time... not rushing it, over the course of leading up to 12 months old.
For me personally, I would introduce a new food after 1 month.
Keep in mind though, that for the first year of life, breastmilk/formula is the PRIMARY source of nutrition for a baby. Usually, solids is given after nursing. If giving solids "before" nursing...this is done to promote "weaning" from breast.
there are lot of different approaches... the point isn't to give the baby 3 meals a day right away...it is to introduce food, slowly, so their system can get used to it, and adapt to it. After all, a baby's digestive system & internal organs are still forming still.
Ask your Pediatrician though...they each have their own approach and ideas about it. Some more conservative and some more liberal.
Don't feel like an "idiot" for asking... any question is important to a Mom no matter how small.
All the best, take care,
~Susan