The first time baby tries solid food, baby won’t take a lot, because they need to learn how to receive the spoon and how to process the food in the mouth, swallow, etc. This is just my way, but at the beginning, I would feed some milk first before giving the solids, then before the nap, I would feed a little more milk. (I did it this way because my baby naturally doesn’t drink a lot of milk at one shot). After a while, when my LO ate a lot more, then I considered that a meal and separated the milk feeding:)
Milk feeds usually not advised to be replaced by solids..typically given after milk. But once baby is taking solids well then you can offer cereal for breakfast, milk for mid morning, porridge for lunch and so on
Initially he only ate a bit so i still give milk as per normal. After some time then we stretched e milk timings