You can be charged with DUI even when you are not driving. Every state has a law that says it is illegal to drive under the influence. What many people do not realize is that most states have some variation of this law that allows police to charge you even when you are not actually driving (DUI parked car).
Depending on the state, a person can often be charged with attempting to drive or operate or being in actual physical control of a vehicle while under the influence. Usually the penalties are the same as for driving under the influence.
Attempting to operate usually means someone is trying to drive the car. In Maine, “operating” means putting power to the wheels and moving the car. Attempting to operate means trying to do that. Trying to operate includes taking a substantial step toward operating.