Summarize this article in one sentence.
Once the engine starts, the alternator produces the electrical charge it needs to keep running. Press the clutch back to the floor with your left foot so you stop accelerating.  With your foot on the clutch, the engine’s RPMs (Revolutions Per Minute) will drop down to an idle. The alternator will recharge the battery and keep the engine running. Keep your foot pressed firmly on the clutch as you push the gear selector forward into the neutral position. This takes the car out of gear. Then use your right foot to apply the brakes and bring the car to a stop.  You can take your left foot off of the clutch once the car is in neutral. Do not shut off the car once you stop. It will take the alternator a while to recharge the battery sufficiently, so leave the engine running once you stop. If the lights were on but the starter was just sluggish, 15 minutes will probably do. However, if the battery was too dead even to turn the lights on, 30 minutes to an hour might be more appropriate.  You can drive the vehicle around while it recharges the battery. If you shut the engine off before the battery is charged enough to start it again, you’ll have to start over.

Summary:
Press the clutch back down after the engine starts. Put the car in neutral and step on the brakes. Let the car run for at least 15 minutes to charge.