Burglary is trespass PLUS an additional criminal act. The intent to commit a criminal act must have been formed before the trespass for the charge of burglary to be proven.
There are different punishments for different fact patterns. Burglary of an occupied dwelling at night with a weapon can be a life felony.
Burglary of an unoccupied building or car is a lesser felony.
To convict someone of burglary the state must prove:
1. An entering of a structure, vehicle or trespass on land.
2. The entering was without permission of the owner.
3. At the time of the entering the defendant had the fully-formed conscious intent to commit a crime (such as a theft, assault, battery, etc.).