where the weasley live after their house r burnt?

No idea why they chose to do that in the movie. I'm guessing they rebuild, as it's used in the seventh book... Unless they change that.

They can build a new house. They're wizards.

They live at Serius's familys old home.

dont they live for a while at a weasley aunts house (while theyre hiding out)? the one that was at bill and fleur's wedding and talke to harry while he was in his disguise as barry o who ever he was.

they go live at their aunt's house

idk