WASHINGTON (AP) — The Supreme Court hears arguments Thursday over whether Donald Trump is immune from prosecution in a case charging him with plotting to overturn the results of the 2020 presidential election.

It’s a historic day for the court, with the justices having an opportunity to decide once and for all whether former presidents can be prosecuted for official acts they take while in the White House.

But between a decades-old court case about Richard Nixon, and an obscure constitutional provision about presidential impeachments, there are likely to be some unfamiliar concepts and terms thrown about.

Here are some tips to help follow everything:

WHEN DOES THE SESSION START?

The court marshal will bang the gavel at 10 a.m. EDT and Chief Justice John Roberts will announce the start of arguments in Donald J. Trump vs. United States of America, as the case is called.