Car wont start. its not the battery because its new.

Well even a new battery can be drained down is you have something on all the time, in about an hour.

So start with checking for a drain.
Remove the battery cables in order to clean and grease them.
Then only put one on.
With everything off if you jump the gap of the cable that is off to the battery, with a test light, is should not light up. If it does, then you have a constant drain that will kill a batter over night.
You have to check for things like interior light, and disconnect everything, one at a time, to pin it down.

If you don't have a drain, then the next thing is to check continuity.
When you turn the ignition on, first the dash indicators come on.
The battery should read 12.5 volts.
Then you try to crank it.
The voltage should drop to 10 while cranking, and come back up after.
If it does not drop to 10, the starter is blocked and not drawing.
It could be the neutral safety switch, so try in neutral instead of park.
It could also be the ignition switch.
Use a test light to see of the small wire plugged into the starter solenoid (the small cylinder on top of the starter), get power when keyed to starter?
If it does not, then ignition switch or neutral safety switch.
If yes, then starter solenoid is probably bad.
But try turning the engine over at the alternator by hand or wrench, and try again. Could be binding between starter and drive plate.

Once you get it started, then rev the engine up and verify alternator goes over 14 volts, to recharge battery.
Otherwise battery will go dead in a day.