Is it true that baby should be introduced first to meat, then to fruits and vegetables when start solid?
Mostly opinion. I give parents some structure to work with, but to my mind, there is no firm nutritional reason--mostly just opinions--to suggest any sequence is better than any other. It has nothing to do with taste, digestibility, allergy risk, etc. The main reason for solids is to teach your baby to handle them (orally), and demonstrate tolerance for a variety of foods. I suggest one new one every few days.
No real rules. There has been a great emphasis on the idea you should start with simple foods to avoid allergic reactions, which I agree with. I've had a couple of babies admitted with food reactions, so it is sometimes a pain. Introducing bland items before sweat ones is supposed to avoid a baby rebellion. Over many decades I don't really think it matters. Mash up something from the community pot and serve.