Why wont vehicle turn over

Is the anti-theft light lit ? Is the starter relay good ? Do you know what a relay is ? Are the battery cables good ? I would start will the starter relay circuit's if the anti-theft light is not lit.! The starter relay along with the starter relay diode is located in the battery junction box in the engine compartment. The relay is K-22 . If you pull out the relay an look on the bottom of the relay you should see four sets of numbers 30,87 an 85 ,86 . If you take a jumper wire (12-14 gage ) an jump pins 30 an 87 if the battery cables & connections are good the starter will crank . Pin's 85 &86 are the control side of the relay . One of these comes from the ignition switch when is start position an the other goes through the transmission range sensor (park neutral switch) To ground or the PCM if yours has a V-8 . Now if when you jump pins 30 & 87 an nothing happens you have bad connections or the battery cable is bad . You can go on youtube an check out videos on voltage drop testing the starter circuit .