Will not start after running out of gas

You may need to just add more gas, as much as five gallons. There's usually a bowl inside the tank where the fuel pickup sits. On my '88 Grand Caravan, when gas was added after running out, the first place it poured into was that bowl, so a quart was enough to get it restarted. On my '94 Grand Caravan, when adding gas, it missed that bowl and went straight into the tank. That left the bowl empty and no gas by the pickup tube. It took five gallons before the level got high enough to spill over into the bowl.

Once the engine is running, the pump moves a lot more gas than the engine uses. The excess goes right back into the tank to keep the bowl full, even when you run down to the last half gallon.

Also listen if you can hear the hum of the fuel pump for one or two seconds when the ignition switch is turned on. While less common, the fuel pump's motor is cooled by the gas in the tank. It is possible for that motor to overheat when the fuel level is really low. That can cause the housing to warp and lock up the pump's motor.

Please let me know if adding gas gets the engine going.