Where is the process for Presidential Impeachment codified?
The US Constitution Article 2, Section 4, states:
The President, Vice President and all civil officers of the United
States, shall be removed from office on impeachment for, and
conviction of, treason, bribery, or other high crimes and
However there are no rules for how the impeachment will proceed in that section.
The process is set out somewhere. Where do these rules originate? What would it take to change them.