1966 Dart troubleshooting

The idle mixture screw two turns out is fairly typical to get you started.
Sorry you are having problems, but it is a good opportunity to learn more about your car. In general they are reliable cars. Carb and ignition work are the most common needs. Once you learn those, it will be easier next time.

Somtimes older cars test new owners, then they settle down and will be good friends.

There are free pdf files for factory service manual online. They provide excellent details on all the service work.
They also have trouble shooting guides.

Once you experience and work with problems they become easier to identify and make repairs in a proactive way.