"Eu quero um quarto para esta noite."
Tradução:I want a room for tonight.
TO is used with "to be").It is also used in cases where a "transfer" happens.
I will give this book to you. (from me to you) I will go to work. (from home to work) I will talk to her. (information goes from me to her)
FOR is used in the following situations:
for the benefit of e.g.- I will do that for you.purpose- This brush is for painting.
Here is an example with both:
Give this book to him but it is for his father.
I will speak to her for you.