Why does it say that you will do to it like to Yericho? The entire city of Yericho was eradicated, and here you will take the spoils!
Malbim: You will burn the city and kill everyone. It is different only regarding the spoils. Since it will not be miraculous, the spoils are permitted.
Why did Hashem say "Tavozu Lachem"?
Rashi: Do not make another Cherem on the spoils.
Radak: It is for all your needs. Nothing will come from it to Otzar Hashem.
Why did Hashem say to make an ambush?
Malbim: This conquest will not be totally miraculous like that of Ai, rather, through war strategy.