Car just turns over will not hit

You need 4 basic things to make an engine run air intake, compression, fuel, spark and exhaust. Check all those things. Cranking the engine and see if there is air coming out the exhaust will eliminate intake and exhaust if u got air conmming out the exhaust... sometimes the cats fall apart and cloug the exhaust causing a similar concern... you can also remove the up strewn o2 sensors and see if it starts But check for fluid also