The Dreaded No Start Issue - common on these cars.
1. Disconnect Neg cable from battery for a few hours, reconnect and then try to start it.
2. Mash Accel Pedal to floor 4 times, try to start it.
3. Check Battery with a Volt Meter - 12+Volts required when not running, 14.5+ Volts running. Check it first in the car connected, or pull it out and any local Auto store can
load test it before spending $$ to replace it. Always remove Negative cable first. You say it is "New" but that does not mean something caused it to drain voltage, or it is not charged properly. A battery can show good voltage, but fail a load test.
4. Check all wire harness connections, especially at the throttle body, and all grounds (battery neg cable at trunk,
ground cable at engine to body, etc). Battery connections at the posts and trunk ground must be clean and tight, use Di-Electric grease to avoid corrosion and ensure a good connection. Key Ground wire checks: (Battery ground negative ground connection to trunk floor, large wire on the passenger side of the engine attached at the front of the head and near the abs block and a tiny wire on the drivers side of the engine near the coolant temp sensor. And, some TB codes will cause a no start condition. Never disconnect any harness connections without disconnecting the Neg cable at the battery. A window reset procedure will then be required, this is easily found in the forum.
5. Get a code reader to determine if there are any codes before spending $$ chasing issues and parts. If you get it running, any auto store (or Dealer) can read them for you.
6. Reprogram the key fob. Insert the key+fob, turn to ON position, let sit for 15 minutes (yes, the car will beep the chime the entire time). Turn to ACC position and wait for a few seconds. At this point that the dash lights flicker on and off for about 30 seconds. There may be a clicking type noise coming from the dash during this 30 seconds. Remove key, wait 5 seconds or so, and reinsert key. Start car.
7. There are lots of reasons for a no start or difficult start - VATs (
https://www.camaro5.com/forums/showthread.php?t=521315), dirty key (really - this happened to my son with a no start and was fixed simply by cleaning the key), Throttle body codes, dirty Throttle Body, grounded out wire harness, poor connection at alternator or bad alternator, heat fried starter, and on and on. Again - reading any codes may pinpoint the exact issue. Too many people replace the battery, Throttle Body, Accel Pedal sensors, Alternator, etc and find it does not fix the issue. MANY times it is just a poor ground connection.
https://www.camaro5.com/forums/showthread.php?t=433174