There is a basic sequence for diagnosing starting problems
1) Does the engine turn over normally ? if it doesn't turn over at all or only does so sluggishly this immediately suggests a problem with the battery or starter motor. If you can jump start it ok that implies a battery problem, either a dead or damaged battery or an electrical fault which is draining it.
2) If the engine turns over but doesn't start this implies a fuel, compression or spark problem. with a modern car this opens up a huge number of potential causes but it is worth checking visually for any loose cables or evidence of a fuel leak.
3) One other possibility is if the engine immobiliser has kicked in this can happen for a number of reasons eg a faulty key transponder or if the alarm has been triggered and not properly reset. It may be worth checking your owners manual to see of there is a reset procedure. The same can also apply if the fuel pump cutoff has been triggered by an impact.
Unless you can find an obvious problem and the car is under warranty just make a warranty claim. There is a very good chance that this is an ECU or sensor issue.