When does jeopardy attach, and what prevents double jeopardy?

First, let's talk about the three types of court settings in this card:

A jury trial is a trial that has a jury. Simple, right?
But what if a defendant waives their right to a jury, or is being tried for a crime that doesn't require a jury? That's called a bench trial, which means a judge, not a jury, decide the defendant's fate.
Finally, a civil proceeding is a civil lawsuit, which means the lawsuit is between two citizens fighting over things that don't involve going to prison.

With that in mind, let's talk about jeopardy. Jeopardy is the peril that a defendant is placed in when the government engages in a trial against them, which automatically means it doesn't apply to civil suits. Under the Constitution, people may only be exposed to the peril of a trial once for any specific crime charged, after which it would be twice the jeopardy, or "double jeopardy" to attempt to try them again for the same crime.

In other words, at a certain point of engagement with a defendant, the government crosses a line and causes "jeopardy to attach," meaning even if they stopped the trial then and there, they have forever lost their chance to bring a trial again in the future for the same charges. In contrast, if they don't cross that line, then they are free to try again later.

So where is that line? In a jury trial, the line is crossed and jeopardy attaches the moment a jury is sworn in. In a bench trial, the line is crossed and jeopardy attaches the moment the first witness is sworn in.