When to/not switch words around?

[Nubcake]

I've been learning french for maybe a month now and its semi good I believe, know a bunch of words, say simple sentances but I get confused when it comes to proper structure.

 

Simple example:

j'ai un livre jaune

i have a book yellow

 

Does it really matter if I switch the words around?

[Aubier]

Hi ! In such a simple sentence, everyone would be able to understand what you mean. Btw, in the example you wrote, it's the proper way to say it.
The meaning can be different in a longer and more complicated sentence, according to the order of the adjective(s). In this case, it will be very subtil. But, don't worry, if you listen to radio or if you watch French movies, you'll get used to proper structures.