The theory behind evolution can happen – the idea that things adapt to their surroundings. Who says that animals today are exactly as they were 5,000 years ago? They might have changed.
However, to say that people came from monkeys or apes is wrong. The Torah says that Hashem created man, and that man was able to speak, reason, etc.
The theory that living things evolved over billions of years is also wrong, as we know the world isn’t even close to that old.
Yes, there are fossils. Do you know why? The Medrash says that whenever Hashem does something miraculous, He does something to make it possible to not believe in it. For example, it says that before Kriyas Yam Suf, the wind blew hard all night. That’s so people who didn’t want to believe in the miracle could claim the wind caused it.
In this case, the fossils are there so that a person could believe Hashem didn’t create the world.
GMAB: congrats. You were fooled by Hashem Himself!