First, check th ebattery by performaing a voltage drop test. Thsi is done with a multi-meter testing the voltage at the battery posts. First check th estatic voltage which should be about 12V. Then see what the voltage is when yuou try to sstart the car. It should not drop much and if it doe s take the battery to an Advance Auto or Auto Zone to get a full diganostic load test done on it. More than likely, it will needd to be replaced if it cannot hold voltage under load.
The next thing to check is the fuel pump relay. It comes on when the key bis turned to the, "ON", position. It should click once and you may be able to hear th efuel pump priming the system.
Then there is the starter relay and solenoid.
The first thing to do is to go to an Advance Auto or Auto Zone and have the trouble codes ran.
Get those and come back to us.